Precision and clarity for your scientific and engineering calculations.
Calculate with 3 Significant Digits
Enter any number. The calculator will identify its significant digits.
Usually 3 for this calculator, but can be adjusted.
Result
—
Value with Specified Significant Digits
Original Number
—
Counted Significant Digits
—
Rounding Rule Applied
—
Calculates significant digits based on standard scientific rules and rounds the number accordingly.
Significant Digits Comparison
Significant Digits Rules Summary
Rule
Description
Example Input
Significant Digits
1
Non-zero digits are always significant.
123
3
2
Zeros between non-zero digits are always significant.
1007
4
3
Leading zeros (zeros before the first non-zero digit) are never significant.
0.0045
2
4
Trailing zeros (zeros at the end of a number) are significant IF the number contains a decimal point.
120.0
4
5
Trailing zeros in a whole number without a decimal point are ambiguous (assume not significant unless specified).
5000
(Ambiguous, often 1)
6
Numbers in scientific notation: all digits are significant.
2.50 x 103
3
Understanding Significant Digits
In the realm of science, engineering, and any quantitative field, precision is paramount. The concept of **significant digits** (often abbreviated as sig figs) is fundamental to accurately representing the precision of a measurement or calculation. It dictates how we interpret numbers, ensuring that we don't overstate or understate the certainty inherent in a value. This **3 significant digits calculator** is designed to help demystify this crucial concept and apply it consistently.
What is 3 Significant Digits?
Significant digits are the digits in a number that carry meaningful contribution to its measurement precision. This includes all digits except leading zeros and sometimes trailing zeros. When we talk about "3 significant digits," we are referring to a number that has exactly three digits that are considered significant according to established rules. For example, the number 12.3 has three significant digits. The number 0.0123 also has three significant digits, as the zeros before the '1' are leading zeros and not significant. The number 1230, however, is ambiguous unless context is provided; it could have 3 or 4 significant digits. Our calculator aims to resolve this ambiguity and provide a clear result when targeting precisely **3 significant digits**.
Who Should Use Significant Digits?
Anyone working with measurements and calculations in a scientific or technical context should understand and use significant digits. This includes:
Students in introductory physics, chemistry, biology, and mathematics courses.
Researchers and scientists in laboratories.
Engineers designing structures, circuits, or systems.
All digits are significant: This is incorrect. Leading zeros are never significant, and trailing zeros can be ambiguous.
Zeros are never significant: This is false. Zeros between non-zero digits are always significant, and trailing zeros *can* be significant if a decimal point is present.
Rounding is arbitrary: While there are rules, rounding to achieve a specific number of significant digits is a systematic process, not a matter of personal preference.
Exact numbers have infinite significant digits: By definition, exact numbers (like counts of objects or defined constants such as 1 meter = 100 centimeters) do not limit precision and are treated as having infinite significant digits.
3 Significant Digits Formula and Mathematical Explanation
The process of determining significant digits and rounding involves two main steps: counting the significant digits in the original number and then rounding or adjusting the number to meet the target count, typically **3 significant digits**. The rules for counting are standardized:
Rules for Counting Significant Digits:
Non-zero digits are always significant. (e.g., in 123.45, the digits 1, 2, 3, 4, and 5 are significant).
Zeros between non-zero digits are always significant. (e.g., in 506.7, the digits 5, 0, 6, and 7 are significant).
Leading zeros (zeros to the left of the first non-zero digit) are *never* significant. They only serve to place the decimal point. (e.g., in 0.0089, the zeros before 8 are not significant; only 8 and 9 are).
Trailing zeros (zeros to the right of the last non-zero digit) are significant *if and only if* the number contains a decimal point. (e.g., in 120.0, the trailing zero after the decimal is significant. In 120, the trailing zero is ambiguous but usually assumed not significant unless indicated otherwise, perhaps by scientific notation like 1.20 x 10³).
Exact numbers (e.g., counted items, definitions) have an infinite number of significant digits and do not limit precision.
Rounding to a Specific Number of Significant Digits (e.g., 3):
Once you've counted the significant digits, you can round the number to the desired precision. Here's how, focusing on obtaining exactly **3 significant digits**:
Identify the digit in the *n*th position (where *n* is your target number of significant digits). This is your last significant digit.
Look at the digit immediately to its right (the *(n+1)*th digit).
If the *(n+1)*th digit is 5 or greater, round up the *n*th digit.
If the *(n+1)*th digit is less than 5, keep the *n*th digit as it is.
Discard all digits to the right of the *n*th digit.
If necessary, add trailing zeros (and a decimal point if appropriate) to maintain the correct place value.
Variable Explanations
Variables in Significant Digit Calculations
Variable
Meaning
Unit
Typical Range
Input Number
The original measured value or number to be analyzed.
Varies (e.g., meters, kilograms, unitless)
Any real number (positive, negative, decimal, integer)
Target Significant Digits
The desired number of significant digits for the output.
Count (integer)
1 to 10 (practical range)
Original Number Display
The input number as entered.
Varies
Same as Input Number
Counted Significant Digits
The number of significant digits present in the original input number.
Count (integer)
0 to many
Rounding Rule Applied
The specific rule used for rounding (e.g., "Round up", "Keep as is").
Text
Descriptive text
Primary Result
The input number rounded to the target number of significant digits.
Varies
Same type as Input Number
Practical Examples (Real-World Use Cases)
Example 1: Measuring Length
Suppose a science student measures the length of a metal rod using a ruler. The ruler's markings are precise, and they read the length as 45.678 centimeters. The student needs to report this measurement to **3 significant digits** for a lab report.
Input Number: 45.678 cm
Target Significant Digits: 3
Calculation Breakdown:
The non-zero digits 4, 5, 6, 7, and 8 are all significant. The original number has 5 significant digits.
We need to round to 3 significant digits. The first three digits are 4, 5, and 6.
Look at the fourth digit, which is 7. Since 7 is greater than or equal to 5, we round up the third digit (6).
The third digit (6) becomes 7.
The result is 45.7 cm.
Calculator Output:
Original Number: 45.678 cm
Counted Significant Digits: 5
Rounding Rule Applied: Round up (due to '7')
Primary Result: 45.7 cm
Interpretation: By reporting 45.7 cm, the student correctly indicates that the measurement is precise to the nearest tenth of a centimeter, reflecting the desired **3 significant digits** of precision.
Example 2: Calculating Density
A chemistry experiment involves measuring the mass of a substance as 125.5 grams and its volume as 50.0 milliliters. Density is calculated as Mass / Volume. We need to report the density to the least number of significant digits from the measurements, which is **3 significant digits** (from 50.0 mL).
Input Number (for demonstration of calculation): 125.5 / 50.0
Target Significant Digits: 3
Calculation Breakdown (Conceptual for calculator):
The calculator internally handles the division and then applies the rounding rules.
Mass: 125.5 g (4 significant digits)
Volume: 50.0 mL (3 significant digits – the trailing zero after the decimal is significant)
Division: Density = 125.5 g / 50.0 mL = 2.51 g/mL
Counting significant digits in the result: 2, 5, and 1 are all significant. The result 2.51 has exactly 3 significant digits.
In this case, the raw result already matches the target of **3 significant digits**, so no further rounding is needed based on the result itself. The limiting factor is the 3 sig figs in the volume.
Calculator Simulation: If you input '2.51' into the calculator, it would show 3 sig figs. If you input '125.5 / 50.0' conceptually, the result is 2.51.
Original Number: 2.51
Counted Significant Digits: 3
Rounding Rule Applied: N/A (Result already has 3 sig figs)
Primary Result: 2.51 g/mL
Interpretation: The density of the substance is reported as 2.51 g/mL. This shows that the calculation respects the precision of the least precise measurement involved (50.0 mL), yielding a result with exactly **3 significant digits**.
How to Use This 3 Significant Digits Calculator
Our **3 significant digits calculator** is straightforward. Follow these steps:
Enter the Number: In the "Input Number" field, type the numerical value you want to analyze or round. This could be a raw measurement, a result from another calculation, or any number you need to represent with a specific precision.
Set Target Digits: The "Target Significant Digits" field defaults to 3. Adjust this if you need to round to a different number of significant digits (though the calculator's primary purpose is focusing on **3 significant digits**).
Click Calculate: Press the "Calculate" button.
Reading the Results:
Primary Result: This is your input number, rounded to the specified number of significant digits (defaulting to **3 significant digits**).
Original Number Display: Shows the exact number you entered.
Counted Significant Digits: Indicates how many significant digits were present in your original input number.
Rounding Rule Applied: Explains whether the last significant digit was rounded up or kept the same.
Decision-Making Guidance:
Use the calculated result to ensure your reported values reflect the true precision of your data. In scientific reporting, using the correct number of **significant digits** is crucial for maintaining data integrity and avoiding misleading conclusions about accuracy.
Key Factors That Affect Significant Digits Results
While the rules for counting and rounding significant digits are standardized, understanding the underlying factors is key to applying them correctly:
Type of Number: Is the number a measurement or an exact count? Measured numbers have inherent uncertainty and thus significant digits. Exact counts (e.g., 5 apples) are considered to have infinite significant digits.
Instrumentation Precision: The measuring instrument used dictates the initial precision of a number. A finely marked ruler allows for more significant digits than a coarse one. This is why a reading like 50.0 mL has more precision (3 sig figs) than 50 mL (ambiguous, potentially only 1 sig fig).
Trailing Zeros: The presence or absence of a decimal point is critical for trailing zeros. 1200 has ambiguous trailing zeros, possibly 2 sig figs. 1200. has 4 sig figs. 1.20 x 10³ also clearly indicates 3 sig figs.
Leading Zeros: These never contribute to the count of significant digits. They merely indicate the magnitude of the number relative to 1. 0.00056 has only 2 significant digits (5 and 6).
Mathematical Operations: When performing calculations (addition, subtraction, multiplication, division), the rules for significant digits change. Multiplication and division results should have the same number of significant digits as the input with the *fewest* significant digits. Addition and subtraction depend on decimal places. Our **3 significant digits calculator** focuses on the rounding of a single number, but understanding these operational rules is vital for subsequent calculations.
Context and Conventions: Sometimes, scientific or engineering fields have specific conventions. For example, a required output format might mandate a certain number of **significant digits** regardless of the input precision. Always be aware of the context in which you are reporting numbers.
Frequently Asked Questions (FAQ)
Q1: How do I know if a zero is significant?
A: Generally, zeros are significant if they are between non-zero digits (e.g., 101) or if they are trailing zeros in a number with a decimal point (e.g., 15.00). Leading zeros (e.g., 0.05) and trailing zeros in whole numbers without a decimal (e.g., 2000) are usually not considered significant unless indicated otherwise (like scientific notation).
Q2: Is 100 exactly 1 significant digit?
A: It's ambiguous. Conventionally, without further information, it's assumed to have 1 significant digit (the '1'). To explicitly state 3 significant digits, you'd write 100. or 1.00 x 102.
Q3: What if my original number has fewer than 3 significant digits?
A: If your original number has, say, 2 significant digits (like 45), and you target 3, the calculator will likely append a zero (resulting in 45.0) and indicate it's a trailing zero made significant by context, or simply state the original number if no rounding is necessary. Our calculator handles this by showing the original count.
Q4: Does the calculator handle negative numbers?
A: Yes, the sign of the number does not affect the count of significant digits. The calculator will process the absolute value for significant digits and maintain the negative sign in the result.
Q5: What's the difference between significant digits and decimal places?
A: Significant digits relate to the precision of the measurement itself, regardless of its magnitude. Decimal places refer to the number of digits after the decimal point. For example, 0.123 has 3 significant digits and 3 decimal places. 123 has 3 significant digits and 0 decimal places.
Q6: Why is rounding to 3 significant digits common?
A: Three significant digits often represents a reasonable balance between precision and practicality in many introductory scientific contexts. It's precise enough to show meaningful variation but not overly complex.
Q7: How do I use the "Copy Results" button?
A: Clicking "Copy Results" will copy the primary result, intermediate values, and key assumptions (like the original number and counted sig figs) to your clipboard, making it easy to paste into documents or notes.
Q8: Can this calculator handle numbers in scientific notation (e.g., 1.23e4)?
A: Yes, you can input numbers like 1.23e4 or 1.23 * 10^4. The calculator recognizes scientific notation and correctly determines the significant digits based on the mantissa (the part before the 'e' or exponent).
Basic Arithmetic Operations– Perform addition, subtraction, multiplication, and division with significant digit considerations.
function isValidNumber(value) {
return !isNaN(parseFloat(value)) && isFinite(value);
}
function countSignificantDigits(numStr) {
if (numStr === null || numStr === undefined || numStr.trim() === "") return 0;
// Handle scientific notation
if (numStr.toLowerCase().includes('e')) {
var parts = numStr.split(/[eE]/);
numStr = parts[0];
}
numStr = numStr.replace(/^[-+]/, "); // Remove sign for counting
numStr = numStr.replace(/,/g, "); // Remove commas
if (numStr === "0") return 1; // Special case for 0
var decimalPointIndex = numStr.indexOf('.');
var nonZeroFound = false;
var sigFigCount = 0;
var roundingRule = "N/A";
var lastSigFigIndex = -1;
for (var i = 0; i < numStr.length; i++) {
var char = numStr[i];
if (char === '.') {
continue; // Skip decimal point
}
if (char === '0') {
// Leading zeros: never significant
if (!nonZeroFound) {
continue;
}
// Trailing zeros: significant if decimal point exists
else {
if (decimalPointIndex !== -1) {
sigFigCount++;
lastSigFigIndex = i;
}
}
} else {
// Non-zero digits are always significant
nonZeroFound = true;
sigFigCount++;
lastSigFigIndex = i;
}
}
// Rule 5: Trailing zeros in whole numbers without a decimal point are ambiguous.
// Conventionally, assume not significant unless indicated.
// For this purpose, we will count them ONLY if they are the last digit and not followed by a decimal.
// However, the rounding logic will handle precision better.
// The sigFigCount calculated above mostly follows standard rules.
return { count: sigFigCount, lastIndex: lastSigFigIndex };
}
function roundToSignificantDigits(numStr, targetDigits) {
var originalNum = parseFloat(numStr);
if (isNaN(originalNum)) return { value: NaN, rule: "Invalid Input" };
var sign = originalNum < 0 ? -1 : 1;
var absNumStr = Math.abs(numStr).toString();
// Handle scientific notation for processing
var isScientific = absNumStr.toLowerCase().includes('e');
var exponent = 0;
if (isScientific) {
var parts = absNumStr.split(/[eE]/);
absNumStr = parts[0];
exponent = parseInt(parts[1], 10);
}
// Remove commas
absNumStr = absNumStr.replace(/,/g, '');
var resultStr = "";
var roundingRule = "Keep as is";
var sigFigInfo = countSignificantDigits(absNumStr);
var currentSigFigs = sigFigInfo.count;
var lastSigFigIndex = sigFigInfo.lastIndex;
if (targetDigits <= 0) {
return { value: NaN, rule: "Target digits must be positive" };
}
if (currentSigFigs === targetDigits && !isScientific) {
// If the number of sig figs already matches and it's not scientific notation,
// we don't need to round unless the original input was ambiguous trailing zeros.
// For simplicity, we return the original number's parsed float value here.
// If the goal is STRICTLY to ensure *exactly* targetDigits, we might need more complex logic.
// However, often the goal is "at least" or "rounded to".
// Let's proceed with rounding logic to ensure it.
}
// Find the target digit position
var targetDigitPos = -1; // Index in the string representing the last significant digit
var currentDigitCount = 0;
var decimalPointIndex = absNumStr.indexOf('.');
for (var i = 0; i < absNumStr.length; i++) {
var char = absNumStr[i];
if (char === '.') continue;
// Leading zeros are not significant
if (char === '0' && !currentDigitCount) continue;
currentDigitCount++;
if (currentDigitCount === targetDigits) {
targetDigitPos = i;
break;
}
}
// Handle cases where targetDigits exceeds available significant digits
if (targetDigitPos === -1) {
// This means the original number has fewer significant digits than requested.
// We should return the original number and indicate it couldn't be rounded up.
// Or, we pad with zeros if a decimal exists.
var paddedNumStr = absNumStr;
if (decimalPointIndex === -1) { // Whole number
// Pad with zeros if necessary to reach targetDigits, assuming trailing zeros become significant
while(countSignificantDigits(paddedNumStr).count < targetDigits) {
paddedNumStr += '0';
}
roundingRule = "Padded with trailing zeros";
} else { // Decimal number
// Find the position of the last significant digit in the original number
var actualLastSigFigIndex = -1;
var tempCount = 0;
for(var i = 0; i < absNumStr.length; ++i) {
var char = absNumStr[i];
if (char === '.') continue;
if (char === '0' && !tempCount) continue; // Leading zero
tempCount++;
actualLastSigFigIndex = i;
}
if (actualLastSigFigIndex < targetDigits -1 && decimalPointIndex !== -1) {
// Need to pad with zeros after the decimal if the original had a decimal
// Pad with zeros to reach targetDigits after decimal point
while (countSignificantDigits(paddedNumStr).count < targetDigits) {
paddedNumStr += '0';
}
roundingRule = "Padded with trailing zeros";
} else {
// Already have enough digits or the original was just small.
// This scenario needs careful handling. If original is '1.2' and target is 3, it becomes '1.20'.
// We just need to ensure the result has targetDigits.
while(countSignificantDigits(paddedNumStr).count = 5;
if (roundUp) {
roundingRule = "Round up";
// Handle carry-over
var tempNumArr = absNumStr.split(");
var k = targetDigitPos;
while (k >= 0) {
if (tempNumArr[k] === '.') { // Skip decimal point
k–;
continue;
}
var digit = parseInt(tempNumArr[k], 10);
if (digit 100)
if (k < 0 && absNumStr[0] !== '0') { // Check if we went past beginning and it wasn't just 0.xxx
// If we carried over and the original number wasn't zero,
// we might need to increase the exponent or add a leading '1'.
if (decimalPointIndex === -1 || targetDigitPos < decimalPointIndex) { // Carry happened before or at decimal for whole number part
// For whole numbers or rounding up the integer part
resultStr = '1' + tempNumArr.slice(0, targetDigitPos + 1).join(''); // Prepend 1
exponent++; // Adjust exponent if it was scientific
} else {
resultStr = tempNumArr.join('');
}
} else {
resultStr = tempNumArr.join('');
}
} else {
roundingRule = "Keep as is";
resultStr = absNumStr.substring(0, targetDigitPos + 1);
}
}
}
// Ensure the result has the correct number of significant digits by padding if needed
// This is especially important if rounding resulted in fewer digits or if original had fewer.
var finalSigFigInfo = countSignificantDigits(resultStr.replace('.', '')); // Count sig figs in the potentially rounded string
var finalSigFigCount = finalSigFigInfo.count;
// If the result string has fewer digits than required, pad with zeros.
// Consider the position of the decimal point.
if (finalSigFigCount < targetDigits) {
var tempResultStr = resultStr;
var tempDecimalIndex = tempResultStr.indexOf('.');
// Pad zeros at the end until targetDigits is reached.
// Ensure padding happens after the last significant digit.
while(countSignificantDigits(tempResultStr.replace('.', '')).count < targetDigits) {
// If no decimal point, append zeros.
// If decimal point exists, check if padding is needed after existing digits.
if (tempDecimalIndex === -1 || tempResultStr.length – (tempDecimalIndex !== -1 ? 1 : 0) exponent 0. 12.3 -> exponent 1. 123 -> exponent 2.
// Adjust exponent if it needs to be adjusted from original
if (resultStr.length > 1 && resultStr[0] !== '0') {
exponent = resultStr.length -1;
if(resultStr.indexOf('.') !== -1) { // If decimal exists, adjust exponent based on its position
exponent = resultStr.indexOf('.') > 0 ? resultStr.indexOf('.') -1 : 0;
}
} else if (resultStr.length === 1) {
exponent = 0;
} else { // Handle cases like 0.123 -> exponent -1
exponent = – (resultStr.split('.')[1]?.length || 0) + 1; // Should be -1 for 0.123
// This scientific notation handling is complex. Let's simplify.
// If original was scientific, we aim to keep it scientific if needed.
// The primary result should be the float value, but we can display scientific if needed.
}
} else { // No decimal point
exponent = resultStr.length – 1;
}
// The rounding might have changed the magnitude, requiring exponent adjustment.
// For simplicity, we will return the float value and var JS handle its default representation.
// If the user entered scientific notation, we'll try to maintain it.
}
finalValue = parseFloat(resultStr) * Math.pow(10, exponent) * sign;
// Ensure the final string representation for display aligns with sig figs
var displayStr = finalValue.toString();
var finalDisplaySigFigs = countSignificantDigits(displayStr);
// If the default string representation doesn't match target digits, use scientific notation or pad.
// This is the trickiest part. Let's focus on displaying the numeric value correctly and add padding logic.
if (finalDisplaySigFigs.count !== targetDigits) {
// Attempt to format with trailing zeros if needed, maintaining float representation.
var formattedStr = parseFloat(resultStr).toFixed(targetDigits – 1); // This forces decimal places, not sig figs directly.
// This needs a dedicated function to format to N significant digits.
// For now, we rely on the parsed float value.
}
return { value: finalValue, rule: roundingRule, originalCount: currentSigFigs };
}
function calculateSignificantDigits() {
var inputNumberStr = document.getElementById('inputNumber').value.trim();
var targetDigits = parseInt(document.getElementById('targetDigits').value);
// Clear previous errors
document.getElementById('inputNumberError').textContent = ";
document.getElementById('targetDigitsError').textContent = ";
var validInputs = true;
if (!inputNumberStr) {
document.getElementById('inputNumberError').textContent = 'Please enter a number.';
validInputs = false;
}
if (isNaN(targetDigits) || targetDigits <= 0) {
document.getElementById('targetDigitsError').textContent = 'Please enter a positive integer for target digits.';
validInputs = false;
}
if (!validInputs) {
document.getElementById('primaryResult').textContent = '–';
document.getElementById('originalNumberDisplay').textContent = '–';
document.getElementById('countedSigFigs').textContent = '–';
document.getElementById('roundingRule').textContent = '–';
clearChart();
return;
}
// Try to parse the input number to check for basic validity
var originalNumberParsed = parseFloat(inputNumberStr);
if (isNaN(originalNumberParsed)) {
// Check if it's scientific notation that parseFloat might miss, or invalid characters
// Let's try a more robust parsing attempt
var scientificRegex = /^[+-]?\d+(\.\d+)?([eE][+-]?\d+)?$/;
if (!scientificRegex.test(inputNumberStr)) {
document.getElementById('inputNumberError').textContent = 'Invalid number format.';
validInputs = false;
document.getElementById('primaryResult').textContent = '–';
document.getElementById('originalNumberDisplay').textContent = '–';
document.getElementById('countedSigFigs').textContent = '–';
document.getElementById('roundingRule').textContent = '–';
clearChart();
return;
}
originalNumberParsed = parseFloat(inputNumberStr); // Re-parse if regex passed
}
var sigFigInfo = countSignificantDigits(inputNumberStr);
var countedSigFigs = sigFigInfo.count;
var roundedResult = roundToSignificantDigits(inputNumberStr, targetDigits);
document.getElementById('originalNumberDisplay').textContent = inputNumberStr;
document.getElementById('countedSigFigs').textContent = countedSigFigs;
if (isNaN(roundedResult.value)) {
document.getElementById('primaryResult').textContent = 'Error';
document.getElementById('roundingRule').textContent = roundedResult.rule;
} else {
// Format the primary result to ensure it reflects the target significant digits
// Use toPrecision to get the correct number of significant digits
var formattedResult = roundedResult.value.toPrecision(targetDigits);
document.getElementById('primaryResult').textContent = formattedResult;
document.getElementById('roundingRule').textContent = roundedResult.rule;
}
updateChart(inputNumberStr, targetDigits, countedSigFigs, roundedResult.value);
}
function resetCalculator() {
document.getElementById('inputNumber').value = '1234.56';
document.getElementById('targetDigits').value = '3';
document.getElementById('inputNumberError').textContent = '';
document.getElementById('targetDigitsError').textContent = '';
calculateSignificantDigits(); // Recalculate with default values
}
function copyResults() {
var primaryResult = document.getElementById('primaryResult').textContent;
var originalNumber = document.getElementById('originalNumberDisplay').textContent;
var countedSigFigs = document.getElementById('countedSigFigs').textContent;
var roundingRule = document.getElementById('roundingRule').textContent;
var targetDigits = document.getElementById('targetDigits').value;
if (primaryResult === '–') return; // Nothing to copy
var textToCopy = "— Significant Digits Calculation —" + "\n\n";
textToCopy += "Input Number: " + originalNumber + "\n";
textToCopy += "Target Significant Digits: " + targetDigits + "\n";
textToCopy += "Counted Significant Digits (Original): " + countedSigFigs + "\n";
textToCopy += "Rounding Rule Applied: " + roundingRule + "\n";
textToCopy += "————————————" + "\n";
textToCopy += "Result (" + targetDigits + " Significant Digits): " + primaryResult + "\n";
textToCopy += "————————————";
// Use navigator.clipboard for modern browsers
if (navigator.clipboard && navigator.clipboard.writeText) {
navigator.clipboard.writeText(textToCopy).then(function() {
alert('Results copied to clipboard!');
}).catch(function(err) {
console.error('Could not copy text: ', err);
fallbackCopyTextToClipboard(textToCopy);
});
} else {
fallbackCopyTextToClipboard(textToCopy);
}
}
// Fallback for older browsers
function fallbackCopyTextToClipboard(text) {
var textArea = document.createElement("textarea");
textArea.value = text;
textArea.style.position="fixed";
textArea.style.top = "0";
textArea.style.left = "0";
textArea.style.width = "2em";
textArea.style.height = "2em";
textArea.style.padding = "0";
textArea.style.border = "none";
textArea.style.outline = "none";
textArea.style.boxShadow = "none";
textArea.style.background = "transparent";
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
var successful = document.execCommand('copy');
var msg = successful ? 'successful' : 'unsuccessful';
console.log('Fallback: Copying text command was ' + msg);
alert('Results copied to clipboard!');
} catch (err) {
console.error('Fallback: Oops, unable to copy', err);
alert('Failed to copy results.');
}
document.body.removeChild(textArea);
}
var myChart;
var chartContext = document.getElementById('sigFigChart').getContext('2d');
function updateChart(originalInput, targetDigits, originalSigFigs, roundedValue) {
if (myChart) {
myChart.destroy();
}
var labels = ['Original Number', 'Rounded Result'];
var dataPoints = [];
var originalNumValue = parseFloat(originalInput);
if (!isNaN(originalNumValue)) {
dataPoints.push(originalNumValue);
} else {
dataPoints.push(0); // Placeholder if invalid
}
if (!isNaN(roundedValue)) {
dataPoints.push(roundedValue);
} else {
dataPoints.push(0); // Placeholder if invalid
}
// Add a data point for the original significant figure count for context
labels.push('Original Sig Figs');
dataPoints.push(originalSigFigs); // Represent count as a value on the chart axis for comparison
myChart = new Chart(chartContext, {
type: 'bar', // Use bar chart for discrete values like counts and rounded numbers
data: {
labels: labels,
datasets: [{
label: 'Value / Count',
data: dataPoints,
backgroundColor: [
'rgba(0, 74, 153, 0.6)', // Primary color for original
'rgba(40, 167, 69, 0.6)', // Success color for rounded
'rgba(255, 193, 7, 0.6)' // Warning color for sig fig count
],
borderColor: [
'rgba(0, 74, 153, 1)',
'rgba(40, 167, 69, 1)',
'rgba(255, 193, 7, 1)'
],
borderWidth: 1
}]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
y: {
beginAtZero: true,
title: {
display: true,
text: 'Value / Significant Figure Count'
}
}
},
plugins: {
title: {
display: true,
text: 'Comparison of Original Value, Rounded Value, and Original Sig Fig Count'
},
legend: {
display: false // Hiding legend as labels are clear
}
}
}
});
}
function clearChart() {
if (myChart) {
myChart.destroy();
myChart = null;
}
// Optionally clear canvas content if needed, but destroying chart usually suffices.
}
// Initialize calculator on load
window.onload = function() {
resetCalculator();
};