Time Duration Calculator

Enter the start as a 24-hour time. For example, 09:00 means nine in the morning and 21:00 means nine in the evening. Minutes range from 00 through 59. The calculator requires both fields; a blank start is not silently treated as midnight.

Enter the finish using the same convention. For a same-day interval, the finish must be on or after the start. If it is earlier, choose Next day only when that accurately describes your interval. The component does not guess that every reversed pair represents an overnight session.

Read the hours-and-minutes result together with total minutes. A ninety-minute period is one hour thirty minutes, or 1.5 decimal hours. It is not 1.30 decimal hours. Use the representation required by your notes or scheduling system, and keep the original readings so the calculation can be checked.

For breaks or several work sessions, use the separate time calculator linked below. This page subtracts one start from one end; it does not know whether you took a break, worked continuously or had unpaid time. Copying the interval does not approve a timesheet or apply workplace rounding rules.

Convert each reading to minutes after midnight: hours × 60 + minutes. Subtract start minutes from end minutes. If Next day is selected, add 1,440 minutes to the end first. Divide the result by sixty for complete hours and keep the remainder as minutes. Choosing Next day can describe more than twenty-four hours when the following-day finish is later than the start time; the component follows the dates you selected rather than imposing an unstated overnight shortcut.

Suppose a session begins at 22:30 and ends at 01:15. On the same calendar day, the end would precede the start, so the component rejects that interpretation. Selecting Next day changes the question explicitly. There are ninety minutes from 22:30 to midnight and seventy-five minutes from midnight to 01:15, giving 165 minutes, or two hours and forty-five minutes. Nothing in this calculation subtracts a break. If the session includes an unpaid fifteen-minute break, record that separately and subtract it only when your task calls for net working time. Also distinguish a nominal wall-clock interval from actual elapsed time across a daylight-saving transition. This tool has no date or time-zone inputs, so it cannot resolve a repeated hour or a clock jump. Two identical clock readings with Next day selected mean twenty-four nominal hours here, not a time-zone-aware measurement. For a flight, a cross-zone call or an event spanning a clock change, use timestamps with explicit zones instead. Saving the start, end and Next day setting prevents a later reader from treating the same clock values as a different interval.

Use these examples to verify the mode before entering your own values. Change one setting at a time so you can identify why the result changes. The examples are fixed demonstrations; they are not automatically updated personal data or recommended dates for your own task.

A civil clock can skip or repeat an hour during a daylight-saving change. Without a date and a time zone, a pair of clock readings cannot identify the actual elapsed interval in that situation. Use a dated, zone-aware record when elapsed time matters.

Travel introduces the same issue. Departure at 10:00 in one city and arrival at 12:00 in another does not necessarily mean two hours elapsed. This calculator assumes the readings belong to the same nominal clock, not different local time zones.

For a casual session timer, a measured timer is more appropriate than reconstructing an interval from rounded clock readings. For a planned slot in a calendar, this wall-clock difference provides the stated schedule length. Keep that distinction in a recurring desktop workflow.

Keep the original inputs with the result. A bare number such as five, thirty or one hundred does not tell a later reader whether it represents dates, weekdays, minutes or complete anniversaries. The copy action records the selected calculation context, and it confirms success only after the browser accepts the clipboard operation.

Calculation fields stay on this device. Closing or refreshing the page is not a promise of persistent storage, and no account is needed to use the tool. If an input is incomplete or invalid, the component hides the previous numerical result and explains what needs changing. Do not use an old screenshot as a result for new inputs.

Kepo offers Mac desktop widgets for repeated checks and small personal workflows. You can explore those capabilities through the download page, but this calculator does not automatically transfer its inputs, save a reminder or generate a configured widget. Preserve the result yourself before moving to a desktop workflow.