Use this tool to calculate the total duration between a start time and an end time, even if it spans across midnight.
Calculation Results:
Enter times and click 'Calculate Duration' to see the results.
Understanding the Hours Calculator
Whether you're tracking work hours, managing project timelines, or simply curious about the duration of an event, accurately calculating hours and minutes is essential. Our Hours Calculator simplifies this process, allowing you to quickly determine the time elapsed between any two points in time.
How to Use the Calculator
Enter Start Time: Input the beginning time of your duration in HH:MM format (e.g., 09:00 for 9 AM, 14:30 for 2:30 PM, or 22:00 for 10 PM).
Enter End Time: Input the ending time of your duration in HH:MM format. This can be on the same day or the next day (e.g., 17:00 for 5 PM on the same day, or 02:00 if the duration extends to 2 AM the next day).
Click 'Calculate Duration': The calculator will instantly display the total hours and minutes, as well as the total decimal hours.
Why is this useful?
Workforce Management: Easily calculate employee work shifts, including those that span across midnight.
Project Planning: Determine the exact duration of tasks or project phases.
Event Scheduling: Figure out the length of meetings, webinars, or personal appointments.
Payroll: Convert total hours and minutes into decimal hours, which is often required for payroll systems.
Examples of Use
Let's look at a few scenarios:
Example 1: Standard Work Shift
You start work at 09:00 and finish at 17:30.
Start Time: 09:00
End Time: 17:30
Result: 8 hours and 30 minutes (8.50 decimal hours)
Example 2: Overnight Shift
You start a night shift at 22:00 and finish at 06:00 the next morning.
Start Time: 22:00
End Time: 06:00
Result: 8 hours and 0 minutes (8.00 decimal hours)
Example 3: Short Meeting
A meeting begins at 10:15 and concludes at 11:00.
Start Time: 10:15
End Time: 11:00
Result: 0 hours and 45 minutes (0.75 decimal hours)
How the Calculation Works
The calculator first converts both the start and end times into total minutes from midnight. It then subtracts the start minutes from the end minutes. If the end time is numerically earlier than the start time (indicating an overnight duration), it correctly accounts for the 24-hour cycle. Finally, the total duration in minutes is converted back into a user-friendly format of hours and minutes, and also into decimal hours for convenience.
/* Basic Styling for the Calculator – feel free to customize */
.calculator-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
background-color: #f9f9f9;
border: 1px solid #ddd;
padding: 20px;
border-radius: 8px;
max-width: 600px;
margin: 20px auto;
box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
.calculator-container h2 {
color: #333;
text-align: center;
margin-bottom: 20px;
}
.calc-input-group {
margin-bottom: 15px;
}
.calc-input-group label {
display: block;
margin-bottom: 5px;
color: #555;
font-weight: bold;
}
.calc-input-group input[type="text"] {
width: calc(100% – 22px);
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
}
button {
display: block;
width: 100%;
padding: 12px;
background-color: #007bff;
color: white;
border: none;
border-radius: 4px;
font-size: 18px;
cursor: pointer;
transition: background-color 0.3s ease;
margin-top: 20px;
}
button:hover {
background-color: #0056b3;
}
.calc-results {
background-color: #e9f7ef;
border: 1px solid #d4edda;
padding: 15px;
border-radius: 4px;
margin-top: 20px;
}
.calc-results h3 {
color: #28a745;
margin-top: 0;
border-bottom: 1px solid #d4edda;
padding-bottom: 10px;
margin-bottom: 10px;
}
.calc-results p {
margin: 5px 0;
color: #333;
}
.calculator-article {
margin-top: 30px;
padding-top: 20px;
border-top: 1px solid #eee;
}
.calculator-article h2, .calculator-article h3 {
color: #333;
margin-top: 20px;
margin-bottom: 10px;
}
.calculator-article p, .calculator-article ul, .calculator-article ol {
color: #555;
line-height: 1.6;
margin-bottom: 10px;
}
.calculator-article ul, .calculator-article ol {
margin-left: 20px;
}
.calculator-article li {
margin-bottom: 5px;
}
function calculateHours() {
var startTimeInput = document.getElementById("startTime").value;
var endTimeInput = document.getElementById("endTime").value;
var resultDiv = document.getElementById("result");
// Regular expression to validate HH:MM format
var timeRegex = /^([01]?[0-9]|2[0-3]):([0-5][0-9])$/;
if (!timeRegex.test(startTimeInput) || !timeRegex.test(endTimeInput)) {
resultDiv.innerHTML = "Please enter times in valid HH:MM format (e.g., 09:00, 22:30).";
return;
}
var startParts = startTimeInput.split(':');
var endParts = endTimeInput.split(':');
var startHour = parseInt(startParts[0], 10);
var startMinute = parseInt(startParts[1], 10);
var endHour = parseInt(endParts[0], 10);
var endMinute = parseInt(endParts[1], 10);
// Convert times to total minutes from midnight
var startTotalMinutes = startHour * 60 + startMinute;
var endTotalMinutes = endHour * 60 + endMinute;
var durationMinutes;
if (endTotalMinutes >= startTotalMinutes) {
// Standard case: end time is on the same day or later
durationMinutes = endTotalMinutes – startTotalMinutes;
} else {
// Case where duration spans across midnight (e.g., 22:00 to 02:00)
// Calculate minutes from start to midnight, then add minutes from midnight to end
durationMinutes = (24 * 60 – startTotalMinutes) + endTotalMinutes;
}
var totalHours = Math.floor(durationMinutes / 60);
var remainingMinutes = durationMinutes % 60;
var decimalHours = (durationMinutes / 60).toFixed(2); // Two decimal places for precision
resultDiv.innerHTML =
"Total Duration: " + totalHours + " hours and " + remainingMinutes + " minutes" +
"Decimal Hours: " + decimalHours + " hours";
}