Hours Tracker Time Clock

How to Calculate Hours Worked

Calculating hours worked sounds simple until you try it with real shift times. Starting at 7:50, leaving at 4:20, taking a 30-minute lunch: how many hours is that? Here's a step-by-step method that works every time, plus a faster way if you'd rather skip the math.

The basic formula

Hours worked = end time minus start time, minus unpaid breaks.

The tricky part is that time runs on 60-minute hours, not 100. That's where most mistakes happen.

How to calculate hours worked, step by step

Step 1: Convert both times to a 24-hour clock

This avoids AM and PM confusion. For PM times, add 12 to the hour (except 12 PM).

  • 7:50 AM stays 7:50
  • 4:20 PM becomes 16:20

Step 2: Subtract the start time from the end time

If the end minutes are smaller than the start minutes, borrow an hour (60 minutes).

  • 16:20 becomes 15:80
  • 15:80 minus 7:50 = 8 hours 30 minutes

Step 3: Subtract unpaid breaks

  • 8 hours 30 minutes minus a 30-minute lunch = 8 hours 0 minutes

Step 4: Convert to decimal for pay

Payroll uses decimal hours. Divide the minutes by 60. For example, 7 hours 45 minutes is 7.75 hours. Our guide on how to convert time to decimal has a full conversion chart.

What about overnight shifts?

If your shift crosses midnight, add 24 to the end time before subtracting. A shift from 10:00 PM (22:00) to 6:30 AM becomes 30:30 minus 22:00, which is 8 hours 30 minutes before breaks.

Adding up a full week

Calculate each day separately, then add the totals. Add hours and minutes in separate columns, and convert every 60 minutes into an hour. If your weekly total goes over 40 hours, you may be owed overtime. See how to calculate overtime pay.

Common mistakes

  • Treating 7:30 as 7.3 hours instead of 7.5
  • Forgetting to subtract breaks, or subtracting them twice
  • Mixing up AM and PM
  • Rounding every shift in the same direction

These small slips add up over a year. See what timesheet mistakes are costing you.

The faster way: let your phone do it

Instead of doing this math every shift, you can clock in and out and let an app calculate it. Hours Tracker Time Clock:

  • Calculates hours to the minute, with breaks subtracted
  • Handles multiple shifts per day
  • Adds up your week and pay period automatically
  • Shows your earnings and overtime as you work
  • Lets you clock in from a home-screen widget in one tap

Never do time math again

Download Hours Tracker Time Clock on the App Store or Google Play. Want to know your weekly total right now? Read how many hours did I work this week.