.significant-figures-calculator-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background-color: #f9f9f9;
border: 1px solid #ddd;
border-radius: 8px;
padding: 25px;
max-width: 600px;
margin: 20px auto;
box-shadow: 0 4px 8px rgba(0, 0, 0, 0.05);
}
.significant-figures-calculator-container h2 {
color: #333;
text-align: center;
margin-bottom: 20px;
font-size: 1.8em;
}
.significant-figures-calculator-container .input-group {
margin-bottom: 15px;
}
.significant-figures-calculator-container label {
display: block;
margin-bottom: 8px;
color: #555;
font-weight: bold;
}
.significant-figures-calculator-container input[type="text"] {
width: calc(100% – 22px);
padding: 10px;
border: 1px solid #ccc;
border-radius: 5px;
font-size: 1em;
box-sizing: border-box;
}
.significant-figures-calculator-container button {
background-color: #007bff;
color: white;
padding: 12px 20px;
border: none;
border-radius: 5px;
cursor: pointer;
font-size: 1.1em;
width: 100%;
box-sizing: border-box;
transition: background-color 0.3s ease;
}
.significant-figures-calculator-container button:hover {
background-color: #0056b3;
}
.significant-figures-calculator-container .result {
margin-top: 25px;
padding: 15px;
background-color: #e9f7ef;
border: 1px solid #d4edda;
border-radius: 5px;
font-size: 1.2em;
color: #155724;
text-align: center;
font-weight: bold;
}
.significant-figures-calculator-container .result strong {
color: #0a3622;
}
.significant-figures-calculator-container p {
line-height: 1.6;
color: #444;
}
.significant-figures-calculator-container ul {
list-style-type: disc;
margin-left: 20px;
margin-bottom: 15px;
color: #444;
}
.significant-figures-calculator-container ul li {
margin-bottom: 8px;
}
Significant Figures Calculator
The number of significant figures will appear here.
function calculateSignificantFigures() {
var inputNumStr = document.getElementById("inputNumber").value.trim();
var resultDiv = document.getElementById("significantFiguresResult");
if (inputNumStr === "") {
resultDiv.innerHTML = "Please enter a number.";
return;
}
// Remove any leading/trailing plus/minus signs for processing
var processedNumStr = inputNumStr.replace(/^[+-]/, ");
// Handle scientific notation (e.g., 1.23e-4) by taking only the mantissa
var parts = processedNumStr.toLowerCase().split('e');
var mantissa = parts[0];
var hasDecimal = mantissa.includes('.');
// Special case: "0"
if (mantissa === "0") {
resultDiv.innerHTML = "The number of significant figures is: 1";
return;
}
// Special case: numbers like "0.0", "0.00"
// If it starts with "0." and only contains zeros after, count all digits after the decimal plus the leading zero.
// Example: "0.0" has 2 sig figs, "0.00" has 3 sig figs.
if (mantissa.match(/^0\.0*$/)) {
// The length of "0.0" is 3, but it has 2 sig figs. So length – 1.
// The length of "0.00" is 4, but it has 3 sig figs. So length – 1.
resultDiv.innerHTML = "The number of significant figures is: " + (mantissa.length – 1);
return;
}
// Remove decimal point for easier processing of digits
var cleanedMantissa = mantissa.replace('.', ");
var firstNonZero = -1;
for (var i = 0; i = 0; j–) {
if (cleanedMantissa[j] !== '0') {
lastNonZero = j;
break;
}
}
significantFiguresCount = lastNonZero – firstNonZero + 1;
}
resultDiv.innerHTML = "The number of significant figures is: " + significantFiguresCount;
}
Understanding Significant Figures
Significant figures (often called sig figs) are the digits in a number that carry meaning contributing to its precision. They are crucial in scientific and engineering fields to express the reliability of a measurement or calculation. The number of significant figures indicates the certainty of a measurement.
Rules for Determining Significant Figures:
- Non-zero digits: All non-zero digits are always significant.
- Example:
123.45has 5 significant figures. - Example:
678has 3 significant figures.
- Example:
- Zeros between non-zero digits (Captive Zeros): Zeros located between non-zero digits are significant.
- Example:
101has 3 significant figures. - Example:
20.05has 4 significant figures.
- Example:
- Leading Zeros: Zeros that precede all non-zero digits are NOT significant. They merely indicate the position of the decimal point.
- Example:
0.0067has 2 significant figures (6 and 7). - Example:
0.5has 1 significant figure.
- Example:
- Trailing Zeros:
- With a Decimal Point: Trailing zeros (at the end of the number) are significant if the number contains a decimal point.
- Example:
12.30has 4 significant figures. - Example:
100.(with a decimal point) has 3 significant figures. - Example:
0.050has 2 significant figures (5 and the trailing 0).
- Example:
- Without a Decimal Point: Trailing zeros in a number without a decimal point are generally considered NOT significant (they are ambiguous and often just placeholders).
- Example:
1200has 2 significant figures (1 and 2). - Example:
10has 1 significant figure.
- Example:
- With a Decimal Point: Trailing zeros (at the end of the number) are significant if the number contains a decimal point.
- Scientific Notation: All digits in the mantissa (the part before the "x 10^") are significant.
- Example:
1.23 x 10^4has 3 significant figures. - Example:
5.00 x 10^-2has 3 significant figures.
- Example:
How to Use the Calculator:
Simply enter any number into the "Enter a Number" field and click "Calculate Significant Figures". The calculator will apply the standard rules to determine and display the count of significant figures in your input.