What “Hours to Decimal” Means
An hours to decimal conversion turns time written as hours and minutes (like 7:30) into a single number (like 7.5). This format is widely used for payroll, timesheets, billing, job costing, and analytics because a single decimal number is easy to add, compare, and multiply by an hourly rate.
The key detail is that minutes are base-60, not base-10. That means the minutes part must be divided by 60 to become a fraction of an hour. If you write 7:30 as 7.30, you are treating minutes like base-100, which is incorrect and can undercount time.
The Simple Conversion Formula
The conversion is:
Decimal hours = hours + (minutes ÷ 60)
Examples:
- 7:30 → 7 + 30/60 = 7.5
- 1:15 → 1 + 15/60 = 1.25
- 0:06 → 0 + 6/60 = 0.1
Why Payroll Often Uses Tenths or Quarter-Hours
Many organizations don’t store exact minutes. Instead, they round time to a policy step. Two common systems are:
- Tenth-hour rounding (0.1): 6-minute blocks (because 0.1 × 60 = 6 minutes)
- Quarter-hour rounding (0.25): 15-minute blocks
Rounding may be “nearest,” “always up,” or “always down.” Your exact decimal totals can change depending on which policy is required, so this calculator lets you select the step and the rounding direction.
Converting Decimal Hours Back to H:MM
Decimal hours are easy for math, but people usually prefer reading time as hours and minutes. Converting back is straightforward:
- Hours = the whole number part
- Minutes = (decimal part × 60)
Example: 2.75 hours → 2 hours + (0.75 × 60) = 45 minutes → 2:45.
How to Total Multiple Time Entries Correctly
When you have multiple entries, the most accurate method is to total minutes (or seconds) first, then convert once. If you convert each entry to a rounded decimal and then add, you can introduce small rounding differences. The Time Entry Sum tab totals at minute precision first and then produces both raw decimal hours and rounded decimal hours.
Common Mistakes and Quick Checks
These quick checks can prevent timesheet errors:
- 0.1 hour = 6 minutes
- 0.25 hour = 15 minutes
- 0.5 hour = 30 minutes
- 0.75 hour = 45 minutes
If your decimals don’t match these patterns, you may be mixing minutes and decimals.
When to Use Strict vs Overflow Minutes
Most times are written with minutes from 0 to 59. Strict mode enforces that and flags input like 1:75 as invalid. However, some exports or manual logs use “overflow minutes” where 1:75 means 1 hour 75 minutes. In those cases, turning off strict validation (or using normalization) can be helpful. This calculator can normalize overflow minutes into standard time for consistent totals.
Best Practices for Payroll and Billing
If you are submitting time to payroll, use the same rounding policy that payroll uses. If you are billing clients, use the billing policy in your contract, which often specifies whether you round up and the minimum increment. If you are tracking personal time, rounding is optional—raw decimals are usually the best for accuracy.
FAQ
Hours to Decimal Calculator – Frequently Asked Questions
Quick answers about converting H:MM to decimal hours, payroll rounding steps, and converting decimals back to minutes.
Use: decimal hours = hours + (minutes ÷ 60). Example: 7:30 = 7 + 30/60 = 7.5.
Because minutes are base-60. 15 minutes is 15/60 = 0.25 hours, so 1:15 becomes 1.25.
6 minutes is 0.1 hours because 6 ÷ 60 = 0.1 (this is why tenth-hour rounding uses 6-minute blocks).
15 minutes is 0.25 hours. Quarter-hour rounding uses 15-minute blocks.
Hours is the whole number. Minutes = (decimal part × 60). Example: 2.75 hours = 2:45.
Yes. Use the Rounding Settings tab to round to quarter-hours, tenth-hours, or other steps, with nearest/up/down modes.
Yes. Use the Time Entry Sum tab to add multiple H:MM entries and get a total in both H:MM and decimal hours.
Follow your employer policy. Some require exact time, while others use rounding increments. This tool supports both.
No. It runs in your browser and does not store your entries.