On This Page
- How to convert time to decimal
- How to convert decimal to time
- Time card and payroll
- Minutes to decimal reference table
- Time to decimal in Excel
- How this calculator is verified
- FAQ
How to Convert Time to Decimal
Divide the minutes by 60, not 100, and add the result to the hours. An hour has 60 minutes, so 45 minutes is 45/60 = 0.75 hours, not 0.45. Nearly every time-conversion mistake comes from treating the minutes as if they were hundredths. The full conversion adds seconds as a fraction of 3,600:
- 1 h 30 m = 1 + 0.5 = 1.5
- 2 h 45 m = 2 + 0.75 = 2.75
- 0 h 15 m = 0.25
- 8 h 20 m = 8 + 0.3333 = 8.3333
- 7 h 48 m = 7 + 0.8 = 7.8
Only a few minute values give clean decimals: 15, 30, and 45 minutes, and any multiple of 6 (every 6 minutes is exactly 0.1 hour). Everything else repeats, like 20 minutes = 0.3333.
How to Convert Decimal to Time
Keep the whole number as the hours. Multiply what's left by 60 for the minutes, and if that leaves a fraction, multiply it by 60 again for the seconds.
| Decimal | Hours | Fraction × 60 | Time |
|---|---|---|---|
| 3.6 | 3 | 0.6 × 60 = 36 | 3:36:00 |
| 3.25 | 3 | 0.25 × 60 = 15 | 3:15:00 |
| 0.4167 | 0 | 0.4167 × 60 = 25.002 | about 0:25:00 |
| 0.333 | 0 | 0.333 × 60 = 19.98 | 0:19:59 |
The last row shows why a rounded decimal doesn't always come back as a round time: 0.333 is a little less than one-third of an hour, so it lands one second short of 20 minutes.
Time Card and Payroll
How to Calculate Decimal Hours From a Time Card
Pay is calculated in decimal hours because you can multiply 8.5 by an hourly rate, but not "8:30." The process for one shift:
- Subtract start from end: 8:20 to 16:50 is 8 hours 30 minutes.
- Convert: 8 + 30/60 = 8.5 hours.
- Multiply by the rate: 8.5 × $18.00 = $153.00 gross.
Converting a Week of Time Card Entries
For a week, convert each day first and then add the decimals. Adding HH:MM values directly means carrying at 60, which is where hand totals go wrong.
| Day | Week A | Decimal | Week B | Decimal |
|---|---|---|---|---|
| Mon | 7:45 | 7.75 | 8:15 | 8.25 |
| Tue | 8:30 | 8.5 | 7:50 | 7.8333 |
| Wed | 8:00 | 8.0 | 8:30 | 8.5 |
| Thu | 7:15 | 7.25 | 8:45 | 8.75 |
| Fri | 8:45 | 8.75 | 7:40 | 7.6667 |
| Total | 40.25 | 41.0 |
Quarter-Hour Rounding and the 7-Minute Rule
Some employers round each punch to the nearest quarter hour: 1 to 7 minutes past rounds down, 8 to 14 rounds up. Others round to 6-minute (0.1 hour) steps. The 7-minute rule and FLSA time rounding guide covers when that's allowed. If you'd rather enter start and end times, with breaks, overnight shifts, and overtime handled for you, use the Work Hours Calculator. Once you have gross pay, the Gross to Net Pay Calculator estimates take-home pay.
Minutes to Decimal Reference Table
Every minute from 1 to 60 as a decimal of an hour (minutes ÷ 60):
| Minutes | Decimal | Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|---|---|
| 1 | 0.0167 | 21 | 0.35 | 41 | 0.6833 |
| 2 | 0.0333 | 22 | 0.3667 | 42 | 0.7 |
| 3 | 0.05 | 23 | 0.3833 | 43 | 0.7167 |
| 4 | 0.0667 | 24 | 0.4 | 44 | 0.7333 |
| 5 | 0.0833 | 25 | 0.4167 | 45 | 0.75 |
| 6 | 0.1 | 26 | 0.4333 | 46 | 0.7667 |
| 7 | 0.1167 | 27 | 0.45 | 47 | 0.7833 |
| 8 | 0.1333 | 28 | 0.4667 | 48 | 0.8 |
| 9 | 0.15 | 29 | 0.4833 | 49 | 0.8167 |
| 10 | 0.1667 | 30 | 0.5 | 50 | 0.8333 |
| 11 | 0.1833 | 31 | 0.5167 | 51 | 0.85 |
| 12 | 0.2 | 32 | 0.5333 | 52 | 0.8667 |
| 13 | 0.2167 | 33 | 0.55 | 53 | 0.8833 |
| 14 | 0.2333 | 34 | 0.5667 | 54 | 0.9 |
| 15 | 0.25 | 35 | 0.5833 | 55 | 0.9167 |
| 16 | 0.2667 | 36 | 0.6 | 56 | 0.9333 |
| 17 | 0.2833 | 37 | 0.6167 | 57 | 0.95 |
| 18 | 0.3 | 38 | 0.6333 | 58 | 0.9667 |
| 19 | 0.3167 | 39 | 0.65 | 59 | 0.9833 |
| 20 | 0.3333 | 40 | 0.6667 | 60 | 1.0 |
Time to Decimal in Excel
Excel stores a time as a fraction of a day, so 0.5 means 12:00 noon, not half an hour. Multiplying by 24 turns it into hours. Forget the 24 and your result is 24 times too small.
| You have | Formula | Example |
|---|---|---|
| An Excel time in A1 | =A1*24 | 0:30 → 0.5 |
| Start in A1, end in B1 | =(B1-A1)*24 | 09:20 to 17:55 → 8.5833 |
| Hours in A1, minutes in B1 as plain numbers | =A1+B1/60 | 2 and 45 → 2.75 |
| Text "2:45" in A1 | =HOUR(TIMEVALUE(A1))+MINUTE(TIMEVALUE(A1))/60 | 2.75 |
Decimal to Time in Excel
To turn decimal hours back into a time, use =A1/24 and format the cell as [h]:mm. The square brackets matter: plain h:mm wraps back to 0 after 24 hours, which silently breaks weekly totals. To pull out the minutes as a number, use =ROUND((A1-INT(A1))*60,0) rather than INT on its own. Decimals like 7.8 are stored as 7.7999..., so =INT((A1-INT(A1))*60) returns 47 instead of 48. This calculator avoids that by rounding to the nearest whole second before splitting out hours and minutes.
How This Calculator Is Verified
Enter 0.333 decimal hours and you get 00:19:59, not 00:19:58.8, because the reverse conversion rounds decimal × 3600 to the nearest whole second with Math.round before splitting it into hours, minutes, and seconds. The forward direction adds three independent terms, hours + minutes/60 + seconds/3600, and also reports the total in minutes. Minute and second inputs are clamped to 0 to 59 as they're read, so typing 75 minutes is treated as 59 rather than spilling into the next hour.
Frequently Asked Questions
How do you convert time to decimal?
Hours as a whole number, plus minutes ÷ 60, plus seconds ÷ 3600. For 2 hours 45 minutes: 2 + (45 ÷ 60) = 2 + 0.75 = 2.75 decimal hours. The most common mistake is dividing by 100, minutes are out of 60, not 100.
How do you convert decimal hours back to hours and minutes?
The whole number is the hours. Multiply the decimal part by 60 to get minutes. For 3.25: hours = 3, minutes = 0.25 × 60 = 15 → 3 hours 15 minutes. Use Decimal → Time mode in the calculator above.
What are 15, 30, and 45 minutes as decimals?
15 min = 0.25, 30 min = 0.5, 45 min = 0.75, 60 min = 1.0. These four values cover the most common payroll increments. Any other minute value is simply minutes ÷ 60: 20 min = 0.3333, 40 min = 0.6667.
Why do you divide by 60 and not 100?
There are 60 minutes in an hour, not 100. Time uses base 60 (sexagesimal), while decimals use base 10. If time were decimal, 1:30 would mean 1.30 hours, but it does not. 1:30 means 1 + 30/60 = 1.5 hours. That mismatch is the entire reason conversion is necessary.
What is 1.5 hours in hours and minutes?
1 hour 30 minutes. The whole number is the hours; 0.5 × 60 = 30 minutes. More examples: 2.25 = 2h 15m, 4.75 = 4h 45m, 7.333 = 7h 20m.
References
- Calculate time difference in Excel, Microsoft Support: official Excel guidance on time arithmetic, the *24 conversion, and HH:MM formatting.
- Fair Labor Standards Act, US Department of Labor: federal rules governing payroll calculation, overtime, and recordkeeping requirements for hourly workers.