Time & Decimal Hours Reference
This is a single-page reference for the time maths that comes up on timesheets and in payroll: converting minutes to decimal hours, common workday and break values, and the rounding rules most systems use. Bookmark it, or print the tables and keep them next to your clock. Every value below is exact to the decimals shown.
The one formula
Decimal hours express minutes as a fraction of an hour. Because there are 60 minutes in an hour, you divide the minutes by 60 and add the result to the whole hours:
Decimal Hours = Hours + (Minutes ÷ 60)
To go back the other way, multiply decimal hours by 60 to get total minutes, then split into whole hours and the remainder.
Quick conversions to memorise
Four values cover the majority of what appears on a real timesheet:
| Minutes | Decimal hours | Fraction |
|---|---|---|
| 6 min | 0.10 | 1/10 hour |
| 15 min | 0.25 | 1/4 hour |
| 30 min | 0.50 | 1/2 hour |
| 45 min | 0.75 | 3/4 hour |
For anything else, use the Decimal Hours Calculator to convert either way, or the Minutes to Hours Calculator for a straight minutes-to-hours answer.
Minutes to decimal hours: full table (1–60)
Every minute value from 1 to 60, to four decimal places. The recurring values (thirds and sixths of an hour) are shown rounded; the exact fraction is in brackets where it helps.
| Min | Decimal | Min | Decimal | Min | Decimal |
|---|---|---|---|---|---|
| 1 | 0.0167 | 21 | 0.3500 | 41 | 0.6833 |
| 2 | 0.0333 | 22 | 0.3667 | 42 | 0.7000 |
| 3 | 0.0500 | 23 | 0.3833 | 43 | 0.7167 |
| 4 | 0.0667 | 24 | 0.4000 | 44 | 0.7333 |
| 5 | 0.0833 | 25 | 0.4167 | 45 | 0.7500 |
| 6 | 0.1000 | 26 | 0.4333 | 46 | 0.7667 |
| 7 | 0.1167 | 27 | 0.4500 | 47 | 0.7833 |
| 8 | 0.1333 | 28 | 0.4667 | 48 | 0.8000 |
| 9 | 0.1500 | 29 | 0.4833 | 49 | 0.8167 |
| 10 | 0.1667 | 30 | 0.5000 | 50 | 0.8333 |
| 11 | 0.1833 | 31 | 0.5167 | 51 | 0.8500 |
| 12 | 0.2000 | 32 | 0.5333 | 52 | 0.8667 |
| 13 | 0.2167 | 33 | 0.5500 | 53 | 0.8833 |
| 14 | 0.2333 | 34 | 0.5667 | 54 | 0.9000 |
| 15 | 0.2500 | 35 | 0.5833 | 55 | 0.9167 |
| 16 | 0.2667 | 36 | 0.6000 | 56 | 0.9333 |
| 17 | 0.2833 | 37 | 0.6167 | 57 | 0.9500 |
| 18 | 0.3000 | 38 | 0.6333 | 58 | 0.9667 |
| 19 | 0.3167 | 39 | 0.6500 | 59 | 0.9833 |
| 20 | 0.3333 | 40 | 0.6667 | 60 | 1.0000 |
Decimal hours back to hours and minutes
Multiply the decimal hours by 60 to get total minutes, then split into whole hours and the remainder:
| Decimal hours | × 60 = minutes | Hours & minutes |
|---|---|---|
| 7.25 | 435 | 7h 15m |
| 7.50 | 450 | 7h 30m |
| 7.75 | 465 | 7h 45m |
| 8.25 | 495 | 8h 15m |
| 0.50 | 30 | 0h 30m |
Hours to minutes
Multiply hours by 60. Useful when a system stores hours but you need the raw minute count.
| Hours | Minutes |
|---|---|
| 0.25 | 15 |
| 0.50 | 30 |
| 1.00 | 60 |
| 2.50 | 150 |
| 7.50 | 450 |
| 8.00 | 480 |
Common workday lengths
Typical worked-time figures after an unpaid break, in both formats.
| Pattern | Hours & minutes | Decimal hours |
|---|---|---|
| 9:00–17:00, no break | 8h 00m | 8.00 |
| 9:00–17:00, 30m unpaid lunch | 7h 30m | 7.50 |
| 9:00–17:30, 30m unpaid lunch | 8h 00m | 8.00 |
| 9:00–18:00, 60m unpaid lunch | 8h 00m | 8.00 |
| 8:00–16:30, 30m unpaid lunch | 7h 30m | 7.50 |
| 22:00–06:00, no break (overnight) | 8h 00m | 8.00 |
| Part-time 9:00–13:00, no break | 4h 00m | 4.00 |
The Work Hours Calculator and Shift Calculator work these out from start and end times with a break field.
Break deduction examples
How an unpaid break reduces worked time. Only unpaid breaks are deducted — a paid break stays in the total.
| Shift span | Unpaid break | Worked | Decimal |
|---|---|---|---|
| 8h 30m | 30m | 8h 00m | 8.00 |
| 8h 30m | 45m | 7h 45m | 7.75 |
| 8h 30m | 60m | 7h 30m | 7.50 |
| 9h 00m | 60m | 8h 00m | 8.00 |
| 6h 00m | 20m | 5h 40m | 5.67 |
For break duration, your return time, or worked hours after lunch, use the Lunch Break Calculator.
Timesheet / payroll examples
Convert each day to decimal hours, then add the decimals. No minute-carrying needed because decimals add like ordinary numbers.
| Day | Worked | Decimal |
|---|---|---|
| Mon | 8h 00m | 8.00 |
| Tue | 7h 30m | 7.50 |
| Wed | 8h 00m | 8.00 |
| Thu | 7h 45m | 7.75 |
| Fri | 8h 00m | 8.00 |
| Week | 39h 15m | 39.25 |
At $20/hour that week is 39.25 × $20 = $785.00 gross. The Timesheet Calculator totals weekly and biweekly entries in both formats, and the Time Card Calculator does the same from clock-in and clock-out times with overtime split out. For the full walkthrough of how these totals are built, see Timesheet Hours & Payroll Calculations Explained.
Why 7:30 is 7.50, not 7.30
This is the single most common decimal-hours mistake. Clock time uses 60 minutes per hour; decimal notation uses base 10. So 30 minutes is half of 60 — that is 0.50 of an hour — giving 7h 30m = 7.50 decimal hours.
Writing 7.30 would mean 7 hours and 30 hundredths of an hour. Thirty hundredths of an hour is 0.30 × 60 = 18 minutes, so 7.30 hours is really 7h 18m — not 7h 30m. The same trap catches 7:45 (which is 7.75, not 7.45) and 7:15 (which is 7.25, not 7.15). For the full explanation, see our Decimal Hours Explained guide.
Rounding
Most payroll systems round decimal hours to two decimals for display and storage. The safe order of operations is: convert first, total second, round last. Rounding each entry before totalling drifts the week's total — ten entries each rounded down by 0.005 lose three minutes across a week.
Some employers round clock times (not decimal hours) to the nearest 1/10, 1/4 or 1/2 hour before calculating. That is a policy choice, not a maths rule, and it varies by employer and jurisdiction. This reference shows the exact maths; check your own agreement for any rounding policy that applies on top.
| Exact | 2-decimal (rounded) |
|---|---|
| 7.8333 (7h 50m) | 7.83 |
| 7.1667 (7h 10m) | 7.17 |
| 2.1667 (2h 10m) | 2.17 |
| 0.0833 (5 min) | 0.08 |
FAQs
- What is 30 minutes in decimal hours?
- 30 ÷ 60 = 0.50, so 30 minutes is 0.50 decimal hours — half an hour. It is not 0.30.
- What is 45 minutes as a decimal?
- 45 ÷ 60 = 0.75, so 45 minutes is 0.75 decimal hours — three quarters of an hour.
- What is 6 minutes in decimal hours?
- 6 ÷ 60 = 0.10, so 6 minutes is 0.10 decimal hours — one tenth of an hour. This is why some systems that round to tenths count 6 minutes as one unit.
- Why is 7:30 equal to 7.5 hours?
- 30 minutes is half of 60, so it is 0.50 of an hour, giving 7 + 0.50 = 7.50 decimal hours. Writing 7.30 treats the minutes as hundredths, which is only 18 minutes.
- How do I convert decimal hours back to minutes?
- Multiply the decimal hours by 60 to get total minutes, then split into whole hours and the remainder. 7.75 × 60 = 465 minutes = 7h 45m.
- How should I round decimal hours?
- Convert first, total second, round last — usually to two decimals. Rounding each entry before totalling drifts the weekly total. Some employers round clock times to the nearest 1/4 or 1/10 hour as a policy; check your own agreement.
- What decimal is 20 minutes?
- 20 ÷ 60 = 0.3333, so 20 minutes is about 0.33 decimal hours — one third of an hour.