AM–PM Calculator

Find elapsed time without guessing at the clock

A start time of 9:00 AM and a finish of 5:30 PM are 8 hours 30 minutes apart. That is the time between the two clock readings, before any break is taken away. If you need to check a timecard, keep the elapsed span separate from the hours actually worked. A lunch break may change the worked total, but it cannot change the start and finish clocks.

This calculator answers one question: how much time elapsed between two 12-hour clock times? It also shows the same duration in decimal hours. It does not ask for a date, unpaid break, hourly rate or overtime rule. For a full timecard with breaks, use the Timesheet Calculator after confirming the clock times here.

Enter the start and end clocks

1. Enter the start hour from 1 to 12, minutes from 00 to 59, and AM or PM. Repeat for the end time. The fields describe clock readings, not hours already worked.
2. If the finish is on the following calendar day, select End time is on the next day. Leave it off for two times on the same day. You must choose this even when a late-night start and early-morning finish look obviously overnight to you.
3. Read elapsed time in hours and minutes, then the two-decimal-hour equivalent. The result updates as you edit. Calculate checks the fields and moves focus to the first invalid entry; Reset restores the 9:00 AM to 5:30 PM example.

The form accepts a single digit for minutes, so entering 5 means 05. It does not accept minute 60, hour 0 or hour 13. If a same-day end is earlier than its start, the form asks you to correct the end time or choose next day. It keeps your entries visible while you make that correction.

Example: 9:00 AM to 5:30 PM

Suppose a timesheet shows a 9:00 AM clock-in and 5:30 PM clock-out on the same date. Set Start to 9:00 AM and End to 5:30 PM, leaving the next-day choice off. From 9:00 AM to noon is 3 hours; from noon to 5:30 PM is 5 hours 30 minutes. Together they make 8 hours 30 minutes of elapsed time.

If the record also includes a 30-minute unpaid break, this form still shows 8 hours 30 minutes. The worked-time amount for that example would be 8 hours after subtracting the break once. Use the main timesheet tool for that separate step; do not read this elapsed-time answer as a payroll-approved paid-hours figure.

When the end time is tomorrow

An overnight record needs an explicit day boundary. Start at 10:00 PM, finish at 6:00 AM, and select next day. There are 2 hours until midnight and 6 more hours after it, giving 8 hours elapsed. Without the next-day choice, the finish is earlier on the same reference date and the calculator shows a correction message instead of a negative answer.

Equal clock times also need a decision. From 9:00 AM to 9:00 AM on the same day, zero time elapsed. If the end is 9:00 AM the next day, the elapsed span is 24 hours. A zero result is therefore valid when the two same-day clocks match; it is not a placeholder for a missing entry.

Check noon, midnight and decimal hours

12:00 AM is midnight, the start of a calendar day. 12:00 PM is noon. For example, 12:00 PM to 1:00 PM is one hour; 12:00 AM to 12:00 PM is twelve hours. Choosing the wrong meridiem can move a result by twelve hours, so compare each selection with the source record before using the total elsewhere.

Minutes are parts of a 60-minute hour. A duration of 8:45 is 8.75 decimal hours because 45 ÷ 60 is 0.75. It is not 8.45 decimal hours: 0.45 of an hour is 27 minutes. The calculator keeps the elapsed difference in whole minutes and rounds only the displayed decimal-hour equivalent to two places. For instance, one minute appears as 0.02 decimal hours, while its actual duration remains one minute.

These reference rows assume the start and end are on the same day. An example list cannot replace your own record: a minute difference, a changed AM/PM selection or an overnight finish changes the answer. Enter the exact clocks above when you need a duration to check.

What to check before using the answer

Compare both clock readings and their dates with the original punch or schedule. This tool uses a fixed UTC reference day to measure an undated clock span, so it does not model a real location's daylight-saving change. If an actual shift crosses a clock change, recorded elapsed hours may differ from this simple wall-clock calculation; use dated, zone-aware records to settle that case.

The form supports a same-day span or an end on the next day, up to 24 hours. It does not represent a shift across multiple dates. It also makes no decision about whether a break is paid, whether time should be rounded for payroll, or whether overtime applies. If those questions matter, carry the checked clock span to the tool and policy that actually handles them.

Questions about AM and PM time

Related calculators

• Timesheet Calculator adds clock records and unpaid breaks across a week.
• Time to Salary Calculator estimates gross pay when you also have a duration and hourly rate.
• Overtime Calculator separates recorded hours under a selected threshold.