This calculator is designed to perform basic arithmetic operations (addition and subtraction) on measurements expressed in feet and inches. It's a practical tool for anyone working with measurements in construction, DIY projects, tailoring, or any field where imperial units are commonly used.
How it Works: The Math Behind the Measurement
The core principle is to convert all measurements into a single, consistent unit (inches) before performing the calculation, and then converting the result back into feet and inches. This simplifies the arithmetic process.
Conversion Factors:
1 foot = 12 inches
The Calculation Process:
Convert to Inches: Each measurement (feet and inches) is converted entirely into inches. For example, 5 feet and 6 inches becomes (5 * 12) + 6 = 66 inches.
Perform Operation: The converted inch values are then added or subtracted as per the user's selection.
Convert Back to Feet and Inches: The final result in inches is converted back.
The total number of feet is found by dividing the total inches by 12 and taking the integer part (e.g., 78 inches / 12 = 6 feet with a remainder).
The remaining inches are found using the modulo operator (remainder) of the total inches divided by 12 (e.g., 78 inches % 12 = 6 inches).
This calculator ensures accuracy and convenience when dealing with imperial measurements, eliminating manual conversion errors.
function getInches(feet, inches) {
var totalInches = (parseFloat(feet) * 12) + parseFloat(inches);
return isNaN(totalInches) ? 0 : totalInches;
}
function convertToFeetInches(totalInches) {
if (isNaN(totalInches) || totalInches < 0) {
return "Invalid or negative result";
}
var feet = Math.floor(totalInches / 12);
var inches = totalInches % 12;
// Format inches to two decimal places if necessary, but usually keep as whole number or one decimal for simplicity
// For this calculator, we'll typically expect whole inches as input, so we'll output whole inches.
// If fractional inches are desired, adjust max attribute and this formatting.
return feet + " ft " + inches.toFixed(2) + " in"; // Display with two decimal places for precision
}
function addMeasurements() {
var feet1 = document.getElementById("feet1").value || "0";
var inches1 = document.getElementById("inches1").value || "0";
var feet2 = document.getElementById("feet2").value || "0";
var inches2 = document.getElementById("inches2").value || "0";
var totalInches1 = getInches(feet1, inches1);
var totalInches2 = getInches(feet2, inches2);
var resultInches = totalInches1 + totalInches2;
var resultFeetInches = convertToFeetInches(resultInches);
document.getElementById("calculatedResult").innerText = resultFeetInches;
document.getElementById("result-container").style.display = "block";
}
function subtractMeasurements() {
var feet1 = document.getElementById("feet1").value || "0";
var inches1 = document.getElementById("inches1").value || "0";
var feet2 = document.getElementById("feet2").value || "0";
var inches2 = document.getElementById("inches2").value || "0";
var totalInches1 = getInches(feet1, inches1);
var totalInches2 = getInches(feet2, inches2);
var resultInches = totalInches1 – totalInches2;
var resultFeetInches = convertToFeetInches(resultInches);
document.getElementById("calculatedResult").innerText = resultFeetInches;
document.getElementById("result-container").style.display = "block";
}
function resetFields() {
document.getElementById("feet1").value = "0";
document.getElementById("inches1").value = "0";
document.getElementById("feet2").value = "0";
document.getElementById("inches2").value = "0";
document.getElementById("result-container").style.display = "none";
document.getElementById("calculatedResult").innerText = "";
}