Hours Calculator

Find how many hours between two times — 9:00 AM to 5:00 PM is 8 hours. Overnight shifts and breaks handled automatically, with results in hours and minutes, decimal hours, and total minutes. The Add Time Durations tab also works as an hours + hours calculator — sum any set of time spans.

Quick answer — 9:00 AM to 5:00 PM is 8 hours. With a 30-minute lunch break, it's 7.5 hours worked.

Hours in a day

Hours in a week

168

Hours in a month (avg)

730.5

Hours in a year

8,760

72 hours

3 days

90 minutes

1.5 hours

Time until 4:00 PM today

Tap Now on Start time, then enter 4:00 PM as End — the countdown updates live.

Time format

12-hour with AM/PM (US standard)

Start time

End time

Break

minutes (optional)

Tip: type times without the colon — 915 = 9:15, 9 = 9:00. Overnight shifts (10:00 PM → 6:00 AM) are handled automatically.

Enter your start and end times to see how many hours between them.

Enter the start time — the beginning of your shift, meeting, or task (e.g. 9:00 AM). Tap Now to fill your current time instantly.
Enter the end time — when it finished (e.g. 5:30 PM). Overnight shifts are handled automatically (10:00 PM to 6:00 AM = 8 hours).
Add a break (optional) — type your unpaid break in minutes (e.g. 30) and the total updates instantly. Copy the result with one click.

How to Calculate Hours Between Two Times — Step by Step

The formula is simple: hours = end time − start time − break time.

Convert to minutes — 9:00 AM = 9×60 = 540 minutes; 5:30 PM = 17:30 = 17×60+30 = 1,050 minutes.
Subtract — 1,050 − 540 = 510 minutes = 8 hours 30 minutes.
Subtract breaks — 510 − 30 = 480 minutes = 8 hours.
Convert to decimal (optional) — 480 ÷ 60 = 8.0 hours.

Worked Examples

Example	Calculation	Result
9:00 AM → 5:00 PM	17×60 − 9×60 = 480	8 hours
7:30 AM → 4:45 PM	(16×60+45) − (7×60+30) = 555	9 hours 15 minutes (9.25 decimal)
10:00 PM → 6:00 AM (overnight)	(6+24)×60 − 22×60 = 480	8 hours (overnight)
2:00 PM → 3:30 PM (meeting)	15×60+30 − 14×60 = 90	1 hour 30 minutes (1.5 decimal)
8:10 AM → 8:45 AM (commute)	8×60+45 − 8×60+10 = 35	35 minutes

Time Units in Hours

How many hours in a day, a week, or a month? Here is the quick reference — from a single day up to a century.

Time period	Hours
1 day	24
1 week	168
1 month (28-day)	672
1 month (29-day)	696
1 month (30-day)	720
1 month (31-day)	744
1 month (average)	730.5
1 year (common)	8,760
1 year (leap)	8,784
1 year (average)	8,766
1 decade (2 leap years)	87,648
1 decade (3 leap years)	87,672
1 decade (average)	87,660
1 century	876,600

Need your work hours in a year — with breaks and overtime? See the Work Hours Calculator.

12-hour vs 24-hour clock

AM = ante meridiem (before noon), PM = post meridiem (after noon). 12 AM = midnight (00:00), 12 PM = noon (12:00).
The 24-hour clock uses 0-23 (00:00 = midnight; 0-11 = AM hours, 12-23 = PM hours). Some countries call it military time.
To avoid confusion, use 12 midnight and 12 noon instead of 12 AM / 12 PM.

Break rules

Unpaid meal breaks (usually 30+ minutes where you are fully relieved of duties) should be deducted from total hours.
Short rest breaks of 5-20 minutes are generally considered paid time under federal law and should not be deducted.
Whether a break counts depends on whether it is paid — check your employment agreement and local rules.

Hours Calculator — FAQ

How many hours is 9 to 5?

A 9:00 AM to 5:00 PM day is 8 hours. With a 30-minute lunch break it is 7.5 hours worked — enter your break in the Break field above and the total updates instantly.

How do I calculate hours between two times?

Convert both times to minutes, subtract, then subtract any break: 9:00 AM = 540 minutes and 5:00 PM = 1,020 minutes, so 1,020 − 540 = 480 minutes = 8 hours. See the step-by-step guide below for worked examples.

Does this hours calculator handle overnight shifts?

Yes. When the end time is earlier than the start time (10:00 PM to 6:00 AM), the calculator automatically adds 24 hours and marks the result as overnight — 10:00 PM to 6:00 AM = 8 hours.

How many hours in a day?

There are 24 hours in a day — 24 × 60 = 1,440 minutes.

How many hours in a month?

The average month has 730.5 hours. By calendar month: 28 days = 672 hours, 29 days = 696, 30 days = 720, and 31 days = 744 hours.

How many hours in a week?

There are 168 hours in a week (7 × 24). Need your weekly working hours with breaks and overtime? Use the Work Hours Calculator.

How long is 72 hours?

72 hours is exactly 3 days (72 ÷ 24 = 3).

How many hours is 90 minutes?

90 minutes is 1.5 hours — 90 ÷ 60 = 1.5.

Do I subtract my lunch break?

Subtract unpaid meal breaks (typically 30+ minutes where you are fully relieved of duties). Short rest breaks of 5-20 minutes are generally considered paid and should not be deducted.

How do I convert minutes to decimal hours?

Divide minutes by 60: 30 minutes = 0.50 hours, 45 minutes = 0.75 hours. Convert any HH:MM:SS span with the Time to Decimal Calculator.

What if my start and end times are the same?

The result is 0 hours and the calculator shows a hint asking whether you meant a 24-hour shift — the same times usually mean the input was a mistake.

What is 7:30 AM to 4:45 PM?

7:30 AM to 4:45 PM is 9 hours 15 minutes — (16×60+45) − (7×60+30) = 555 minutes = 9.25 decimal hours.

Can I use this calculator with lunch breaks?

Yes — type your break in minutes in the Break field (e.g. 30 for a 30-minute lunch) and it is deducted from the total automatically.

Is this hours calculator free?

Yes, completely free with no sign-up. All calculations run locally in your browser — your times never leave your device.

How many hours is 12 AM to 12 PM?

12 AM to 12 PM is 12 hours — 12 AM is midnight (00:00) and 12 PM is noon (12:00).

What is the difference between 12-hour and 24-hour time?

The 12-hour clock uses AM/PM with hours 1-12, while the 24-hour clock runs 0-23 (00:00 = midnight, 12:00 = noon, 23:00 = 11 PM). See the clock guide below.

How do I add multiple time durations together?

Use the Add Time Durations tab — enter each span as HH:MM and they are summed (8:30 + 6:15 = 14:45). For 45 minutes, enter 0:45 — the hour part is required.

What is 1:30 + 2:45 in hours?

1 hour 30 minutes + 2 hours 45 minutes = 4 hours 15 minutes (4.25 decimal hours) — minutes roll over to hours once they reach 60.

How many minutes are in an hour?

There are 60 minutes in 1 hour — and 3,600 seconds. To convert hours to minutes, multiply by 60: 2 hours = 120 minutes, 2.5 hours = 150 minutes.

How do I add hours and minutes together?

Use the Add Time Durations tab: enter each span as HH:MM and they are summed instantly (1:15 + 2:30 = 3:45). This works as an hours + hours calculator — minutes roll over to hours once they reach 60.

Disclaimer

This calculator is provided for informational purposes. For official payroll and overtime decisions, verify results with your employer, payroll department, or applicable labor laws.