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. Reverse conversion retains the entered decimal digits in exact fractional arithmetic before rounding. Extremely large durations are rejected when whole cannot be represented safely. Decimal text length and exponent bounds prevent oversized entries; API callers should send a decimal string to preserve its digits.
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.