This decimal hours calculator converts conventional duration parts to decimal hours and converts decimal hours back to hours, minutes, and . Totals stay intact above a full .
Convert between time and decimal hours
Choose the direction that matches the value you already have. The forward mode accepts duration parts, while the reverse mode accepts one decimal-hour total.
Hours and minutes belong in the forward mode. A decimal-hour value belongs in the reverse mode.
Accumulated hours do not reset at midnight or wrap into a time of .
The calculator applies mathematical display and whole- rounding. It does not apply payroll rules.
Example: convert 1 hour 30 minutes and check the reverse
- Enter 1 30 0 in the forward mode and the engine returns 1.5 h.
- Switch to the reverse mode and 1.5 h returns 1 30 0 .
- Both runs represent 5,400 .
Minutes to decimal hours conversion table
Look up any whole minute from 0 through 59. Each row comes from the calculator's internal minute-table mode, which divides the minute value by 60.
| Minutes | Exact hour fraction | Decimal hours |
|---|---|---|
| 0 | 0/1 | 0 |
| 1 | 1/60 | 0.0167 |
| 2 | 1/30 | 0.0333 |
| 3 | 1/20 | 0.05 |
| 4 | 1/15 | 0.0667 |
| 5 | 1/12 | 0.0833 |
| 6 | 1/10 | 0.1 |
| 7 | 7/60 | 0.1167 |
| 8 | 2/15 | 0.1333 |
| 9 | 3/20 | 0.15 |
| 10 | 1/6 | 0.1667 |
| 11 | 11/60 | 0.1833 |
| 12 | 1/5 | 0.2 |
| 13 | 13/60 | 0.2167 |
| 14 | 7/30 | 0.2333 |
| 15 | 1/4 | 0.25 |
| 16 | 4/15 | 0.2667 |
| 17 | 17/60 | 0.2833 |
| 18 | 3/10 | 0.3 |
| 19 | 19/60 | 0.3167 |
| 20 | 1/3 | 0.3333 |
| 21 | 7/20 | 0.35 |
| 22 | 11/30 | 0.3667 |
| 23 | 23/60 | 0.3833 |
| 24 | 2/5 | 0.4 |
| 25 | 5/12 | 0.4167 |
| 26 | 13/30 | 0.4333 |
| 27 | 9/20 | 0.45 |
| 28 | 7/15 | 0.4667 |
| 29 | 29/60 | 0.4833 |
| 30 | 1/2 | 0.5 |
| 31 | 31/60 | 0.5167 |
| 32 | 8/15 | 0.5333 |
| 33 | 11/20 | 0.55 |
| 34 | 17/30 | 0.5667 |
| 35 | 7/12 | 0.5833 |
| 36 | 3/5 | 0.6 |
| 37 | 37/60 | 0.6167 |
| 38 | 19/30 | 0.6333 |
| 39 | 13/20 | 0.65 |
| 40 | 2/3 | 0.6667 |
| 41 | 41/60 | 0.6833 |
| 42 | 7/10 | 0.7 |
| 43 | 43/60 | 0.7167 |
| 44 | 11/15 | 0.7333 |
| 45 | 3/4 | 0.75 |
| 46 | 23/30 | 0.7667 |
| 47 | 47/60 | 0.7833 |
| 48 | 4/5 | 0.8 |
| 49 | 49/60 | 0.8167 |
| 50 | 5/6 | 0.8333 |
| 51 | 17/20 | 0.85 |
| 52 | 13/15 | 0.8667 |
| 53 | 53/60 | 0.8833 |
| 54 | 9/10 | 0.9 |
| 55 | 11/12 | 0.9167 |
| 56 | 14/15 | 0.9333 |
| 57 | 19/20 | 0.95 |
| 58 | 29/30 | 0.9667 |
| 59 | 59/60 | 0.9833 |
Decimal values use the calculator's display rule of up to four places, with trailing zeros removed.
Use the two decimal-hours conversion directions
To convert duration parts to decimal hours, the engine calculates total as hours × 3,600 /h plus minutes × 60 /min plus . It then divides that exact total by 3,600 /h. Minutes and must be whole components within an ordinary hour, while accumulated hours can keep growing. To convert decimal hours back, multiply the full entered decimal-hour value by 3,600 /h, apply the calculator's whole- rounding once, and then split that total into accumulated hours, minutes, and . The Calculator Campus rule sends an exact half- tie to the even whole , so separate intermediate rounding cannot create a stray carry.
Keep rounding and duration notation separate
The four-place decimal display and ties-to-even handling are Calculator Campus product rules. NIST Appendix B.7.1 documents the same exact-halfway convention but does not require this calculator's display length or whole- policy. The reverse calculation starts with the full entered value. For 1.999999 h, the engine gets 7,199.9964 , rounds once to 7,200 , and returns 2 0 0 . Durations do not reset at midnight: 40 15 0 becomes 40.25 h. A decimal point is not a separator for clock minutes. 7.30 h converts to 7 18 0 , while 7 30 0 converts to 7.5 h. This page uses ordinary 60 /h, not a historical base-ten clock. Some spreadsheets store time as a fraction of a , so convert that value to hours before expecting decimal-hour notation. When the source data consists of shifts and unpaid breaks, the work-hours calculator should total those intervals first. For a weekly or two- set of entries, use the time-card calculator. If you have start and end clock readings, begin with the time duration calculator.