Hours ↔ Decimal Converter
Convert hours and minutes to decimal hours and convert decimal hours back to time.
Runs in your browser · No sign-up required
Calculator inputs are loading. If they do not appear, reload the page and check that JavaScript is enabled in your browser.
How this calculator works
Decimal hours use the magnitude |hours| + |minutes| ÷ 60 and one sign for the whole duration. Enter −1 hours and 30 minutes for −1.5 hours, or 0 hours and −30 minutes for −0.5 hours. Negative minutes are only allowed when hours are 0; their magnitude must be less than 60. Converting back rounds to the nearest minute, carrying 60 minutes into the next hour.
Example
8 hours 30 minutes = 8.5 decimal hours. Converting 8.5 back gives 8 hours 30 minutes.
Does a minus sign apply to minutes too?
One sign applies to the whole duration: −1 hours and 30 minutes is −1.5 hours, not −0.5. For a negative duration shorter than an hour, use 0 hours and negative minutes. The reverse direction rounds to a whole minute.
This table scrolls horizontally on small screens.
| Hours ; minutes / decimal-hour input | Conversion | Decimal hours / hours:minutes |
|---|---|---|
| 7 h ; 30 min | 7 + 30/60 | 7.5 |
| −1 h ; 30 min | −(1 + 30/60) | −1.5 |
| 0 h ; −30 min | −30/60 | −0.5 |
| 7.30 decimal hours | 0.30 × 60 | 7:18 |
A mistake to avoid
A minutes magnitude of 60 is invalid; carry it into hours first. Negative minutes are allowed only with zero hours. Select the conversion direction and review signs before reusing a decimal value in a pay field.
Sources and limits
Calculation methodology · 2026-10-12
Frequently asked questions
Is 8 hours 30 minutes written as 8.30?
No. Minutes are a fraction of 60: 30 ÷ 60 = 0.5, so the decimal value is 8.5.
Why can the converted time be slightly different?
The decimal result displays up to four decimal places. Converting back rounds to whole minutes; it does not display seconds.