Convert between fractions, decimals, inches, feet, and metric units instantly.
0 (No Fraction)
1/2
1/4
1/8
1/16
1/32
Inches
Feet
Centimeters (cm)
Millimeters (mm)
Converted Measurements:
Fractional Inches:
Decimal Inches: "
Feet & Inches:
Total Feet: '
Centimeters: cm
Millimeters: mm
How to Use the Measuring Tape Calculator
Whether you are a carpenter, a weekend DIY enthusiast, or a student working on a geometry project, reading a measuring tape accurately is a fundamental skill. This calculator simplifies the process by allowing you to input complex fractions and instantly see their metric and decimal equivalents.
Common Tape Measure Conversions
Standard tape measures in the US typically use inches subdivided into halves, quarters, eighths, and sixteenths. Some high-precision tapes even include thirty-seconds. Here is a quick reference for common fractions:
1/8 inch = 0.125 inches (3.175 mm)
1/4 inch = 0.25 inches (6.35 mm)
3/8 inch = 0.375 inches (9.525 mm)
1/2 inch = 0.5 inches (12.7 mm)
5/8 inch = 0.625 inches (15.875 mm)
3/4 inch = 0.75 inches (19.05 mm)
Converting Fractions to Decimals
To convert a fraction like 5/8 to a decimal manually, you divide the top number (numerator) by the bottom number (denominator). 5 divided by 8 equals 0.625. If you have a measurement like 12 5/8 inches, the decimal equivalent is 12.625 inches. Our calculator does this work for you, including the conversion to metric units (cm and mm).
Understanding Tape Measure Marks
Most tape measures feature different line lengths to help you identify the fraction quickly:
Longest Line: The whole inch mark, accompanied by a large number.
Second Longest: The half-inch (1/2″) mark exactly in the middle.
Third Longest: The quarter-inch (1/4″ and 3/4″) marks.
Shortest Lines: The 1/8″ and 1/16″ marks.
Practical Examples
Example 1: You measure a piece of wood for a bookshelf at 45 3/16 inches.
Calculation: 3 รท 16 = 0.1875. Total = 45.1875 inches. To find the centimeter value, multiply by 2.54, resulting in 114.77 cm.
Example 2: A floor plan lists a room dimension as 14 feet 6 inches.
Calculation: 14 * 12 = 168. 168 + 6 = 174 total inches. 174 inches is exactly 4.4196 meters.
function calculateTape() {
var whole = parseFloat(document.getElementById('wholeValue').value) || 0;
var num = parseFloat(document.getElementById('numPart').value) || 0;
var den = parseFloat(document.getElementById('denPart').value) || 1;
var unit = document.getElementById('inputUnit').value;
var totalInches = 0;
var fractionValue = num / den;
var inputTotal = whole + fractionValue;
// Convert input to total inches base
if (unit === "inches") {
totalInches = inputTotal;
} else if (unit === "feet") {
totalInches = inputTotal * 12;
} else if (unit === "cm") {
totalInches = inputTotal / 2.54;
} else if (unit === "mm") {
totalInches = inputTotal / 25.4;
}
if (isNaN(totalInches) || totalInches < 0) {
alert("Please enter valid positive numbers.");
return;
}
// Calculations
var decimalInches = totalInches.toFixed(4);
var totalFeet = (totalInches / 12).toFixed(4);
var feetPart = Math.floor(totalInches / 12);
var inchPart = totalInches % 12;
// Find closest fraction for the result (to 1/32)
var wholeInchesResult = Math.floor(totalInches);
var remainingDecimal = totalInches – wholeInchesResult;
var closest32nd = Math.round(remainingDecimal * 32);
var fracString = "";
if (closest32nd === 32) {
wholeInchesResult += 1;
fracString = wholeInchesResult + "\"";
} else if (closest32nd === 0) {
fracString = wholeInchesResult + "\"";
} else {
// Simplify fraction
var n = closest32nd;
var d = 32;
var gcd = function(a, b) { return b ? gcd(b, a % b) : a; };
var common = gcd(n, d);
fracString = wholeInchesResult + " " + (n/common) + "/" + (d/common) + "\"";
}
var cmValue = (totalInches * 2.54).toFixed(2);
var mmValue = (totalInches * 25.4).toFixed(1);
// Display results
document.getElementById('resFractional').innerText = fracString;
document.getElementById('resDecimal').innerText = decimalInches;
document.getElementById('resFeetInches').innerText = feetPart + "' " + inchPart.toFixed(2) + "\"";
document.getElementById('resFeetDecimal').innerText = totalFeet;
document.getElementById('resCM').innerText = cmValue;
document.getElementById('resMM').innerText = mmValue;
document.getElementById('tapeResult').style.display = 'block';
}