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Free Military Time Calculator

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Military Time Calculator

A military time calculator adds or subtracts hours and minutes from a 24-hour time and finds the hours between two military times: 0800 + 8 h 30 min = 1630, and 2200 to 0630 is 8 h 30 min. Results show the day change when a calculation crosses midnight.

Result

1630 HRS

4:30 PM · same day

Quick reference

MilitaryStandard
000012:00 AM
06006:00 AM
08008:00 AM
120012:00 PM
13001:00 PM
15003:00 PM
17005:00 PM
18006:00 PM
20008:00 PM
220010:00 PM

How to Add Military Time

To add military time, add the minutes, carry 1 hour for every 60 minutes, then add the hours and wrap past 24. 4 steps cover every sum:

  1. Add the minutes: 0945 + 2 h 30 min → 45 + 30 = 75 minutes.
  2. Carry the hour: 75 minutes = 1 hour 15 minutes.
  3. Add the hours: 9 + 2 + 1 = 12.
  4. Wrap past midnight: subtract 24 from any hour of 24 or more and mark the next day. The result here is 1215.

How to Subtract Military Time

To subtract military time, subtract the minutes first and borrow 60 minutes from the hours when the minutes run short.

  1. Compare the minutes: 1415 − 2 h 30 min → 15 is less than 30.
  2. Borrow 1 hour: 14 h 15 min becomes 13 h 75 min.
  3. Subtract: 13 h 75 min − 2 h 30 min = 11 h 45 min → 1145.
  4. Wrap below midnight: add 24 to a negative hour and mark the previous day. 0100 − 2 h = 2300 the day before.

How to Find the Hours Between Two Military Times

To find the hours between two military times, subtract the start time from the end time using the borrow rule. The method changes when the period crosses midnight.

Same-Day Times

0730 to 1615: 16 h 15 min − 7 h 30 min → borrow → 15 h 75 min − 7 h 30 min = 8 hours 45 minutes.

Times That Cross Midnight

Add 24 hours to the end time, if the end time is earlier than the start time. 2300 to 0700: 0700 + 2400 = 3100, and 3100 − 2300 = 8 hours.

Elapsed Time in Decimal Hours

Divide the leftover minutes by 60 for payroll or billing: 8 hours 45 minutes = 8 + 45 ÷ 60 = 8.75 hours (525 minutes).

4 Mistakes in Military Time Math

  1. Subtracting as base-10 numbers. 1615 − 730 = 885 looks like 8 h 85 min; the right answer is 8 h 45 min.
  2. Writing minutes as decimals. 30 minutes is 0.50 hours, not 0.30.
  3. Forgetting the day change. 2230 + 3 h is 0130 the next day, not 2530.
  4. Subtracting backward across midnight. 2200 to 0600 is 8 hours, not −16 hours.

Military Time Math Examples

These 6 examples cover adding, subtracting and elapsed time, including both midnight cases:

ProblemWorkingAnswer
0945 + 2 h 30 min45 + 30 = 75 min → 1 h 15 min; 9 + 2 + 1 = 121215
2230 + 3 h22 + 3 = 25 → 25 − 24 = 010130 (+1 day)
1415 − 2 h 30 minBorrow: 13 h 75 min − 2 h 30 min1145
0100 − 2 h1 − 2 = −1 → −1 + 24 = 232300 (−1 day)
0730 → 161516 h 15 min − 7 h 30 min8 h 45 min (8.75 h)
2300 → 07000700 + 2400 = 3100; 3100 − 23008 h (8.00 h)

Where the 24-Hour Day Comes From

The 24-hour day comes from ancient Egypt, where the day and the night were each split into 12 hours. The Greek astronomer Hipparchus proposed 24 hours of equal length. Military time counts those 24 equal hours straight through from 0000, which makes time math a matter of base-60 minutes and a 24-hour wrap.

For weekly hours and overtime, use the military time card calculator.

Who Uses This Tool?

4 groups of people use this tool most:

  • Nurses

    Schedule doses every 6 or 8 hours, such as 0600, 1400 and 2200.

  • Pilots and dispatchers

    Add flight or travel durations to a 24-hour departure time.

  • Shift supervisors

    Find the hours between handovers, including overnight shifts.

  • Students

    Check answers to military time math problems.

Military Time Calculator FAQ

How do you add military time?

Add the hours and the minutes separately. Carry 1 hour when the minutes reach 60, and subtract 24 when the hours reach 24; the result is then on the next day. 2230 + 0300 = 0130 the next day.

How do you subtract military time?

Subtract the minutes first and borrow 60 minutes from the hours when needed, then subtract the hours. 1415 − 0230 becomes 13 h 75 min − 2 h 30 min = 1145.

How do I calculate the hours between two military times?

Subtract the start time from the end time, borrowing 60 minutes when needed. Add 24 hours to the end time first, if the end time is earlier than the start time. 0730 to 1615 is 8 hours 45 minutes.

Why can’t I subtract military times as normal numbers?

No, military times are not base-10 numbers: an hour has 60 minutes. 1615 − 730 = 885 as plain numbers, but the real difference is 8 hours 45 minutes.

How do I write elapsed time in decimal hours?

Divide the minutes by 60 and add the hours. 8 hours 45 minutes = 8 + 45 ÷ 60 = 8.75 hours. 30 minutes is 0.50 hours, not 0.30.

Can the calculator handle times past midnight?

Yes, the calculator shows +1 day or −1 day when a sum or difference crosses midnight, and treats an end time earlier than the start time as the next day.