Calculate the duration between two times or add multiple time values together.
1. Calculate Time Duration
Find the hours and minutes between a start and end time.
AM
PM
AM
PM
Duration Result:
2. Add Multiple Time Values
Sum up hours, minutes, and seconds (useful for logbooks or playlists).
Total Time:
How to Calculate Time Duration
Calculating the time between two points in a day is a common task for payroll, project management, and daily planning. To calculate time duration manually, you follow these steps:
Convert both the start and end times into a 24-hour format.
If the end time is "smaller" than the start time (meaning it's the next day), add 24 hours to the end time.
Subtract the start time minutes from the end time minutes.
Subtract the start time hours from the end time hours.
If the minute result is negative, borrow 60 minutes from the hours column.
Using the Time Duration Calculator
Our tool simplifies this process. Simply enter your start time (e.g., 8:30 AM) and your end time (e.g., 5:15 PM). The calculator automatically handles the AM/PM conversion and provides you with the total hours and minutes elapsed.
Example Calculation:
Start Time: 9:45 AM
End Time: 2:15 PM Result: 4 hours and 30 minutes.
Adding Multiple Time Segments
If you are tracking billable hours or looking at a list of video lengths, you often need to sum up multiple durations. The "Time Adder" section allows you to input multiple rows of hours, minutes, and seconds. It then carries over the remainders (60 seconds into 1 minute, 60 minutes into 1 hour) to give you an accurate total.
Common Applications
This calculator is designed for several specific use cases:
Work Shifts: Calculating exactly how long you worked between clock-in and clock-out.
Time Logs: Adding up hours spent on different tasks for a client invoice.
Travel Planning: Determining total travel time across multiple flight legs or train rides.
Athletics: Summing up lap times or training sessions.
function calculateDuration() {
var sh = parseInt(document.getElementById('startH').value);
var sm = parseInt(document.getElementById('startM').value) || 0;
var sap = document.getElementById('startAP').value;
var eh = parseInt(document.getElementById('endH').value);
var em = parseInt(document.getElementById('endM').value) || 0;
var eap = document.getElementById('endAP').value;
if (isNaN(sh) || isNaN(eh)) {
alert("Please enter valid hour values.");
return;
}
// Convert to 24 hour minutes
var startTotalMinutes = convertTo24Mins(sh, sm, sap);
var endTotalMinutes = convertTo24Mins(eh, em, eap);
// Handle crossing midnight
if (endTotalMinutes < startTotalMinutes) {
endTotalMinutes += 1440; // Add 24 hours in minutes
}
var diff = endTotalMinutes – startTotalMinutes;
var resH = Math.floor(diff / 60);
var resM = diff % 60;
var resultDiv = document.getElementById('durationResult');
var resultText = document.getElementById('durationText');
resultDiv.style.display = 'block';
resultText.innerHTML = "" + resH + " hours and " + resM + " minutes(" + diff + " total minutes)";
}
function convertTo24Mins(h, m, ap) {
if (ap === "PM" && h !== 12) h += 12;
if (ap === "AM" && h === 12) h = 0;
return (h * 60) + m;
}
function addMoreRows() {
var container = document.getElementById('timeRows');
var newRow = document.createElement('div');
newRow.className = 'time-calc-row';
newRow.innerHTML = '' +
'' +
'';
container.appendChild(newRow);
}
function sumTimes() {
var hours = document.getElementsByClassName('addH');
var minutes = document.getElementsByClassName('addM');
var seconds = document.getElementsByClassName('addS');
var totalSeconds = 0;
for (var i = 0; i < hours.length; i++) {
var h = parseInt(hours[i].value) || 0;
var m = parseInt(minutes[i].value) || 0;
var s = parseInt(seconds[i].value) || 0;
totalSeconds += (h * 3600) + (m * 60) + s;
}
var finalH = Math.floor(totalSeconds / 3600);
var remainingSeconds = totalSeconds % 3600;
var finalM = Math.floor(remainingSeconds / 60);
var finalS = remainingSeconds % 60;
var resultDiv = document.getElementById('sumResult');
var resultText = document.getElementById('sumText');
resultDiv.style.display = 'block';
resultText.innerHTML = "" + finalH + "h " + finalM + "m " + finalS + "s";
}