Converting minutes to decimal hours
Invoices and timesheets use decimal hours, not hours and minutes: 1 hour 30 minutes is 1.5 hours, not 1.30. To convert, divide the minutes by 60. The table below covers the most common values:
| Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|
| 6 | 0.10 | 36 | 0.60 |
| 12 | 0.20 | 42 | 0.70 |
| 15 | 0.25 | 45 | 0.75 |
| 18 | 0.30 | 48 | 0.80 |
| 24 | 0.40 | 54 | 0.90 |
| 30 | 0.50 | 60 | 1.00 |
Which rounding rule should you use?
Rounding is standard practice, but it must be consistent and disclosed to the client in your terms. The most common increments are:
- 6 minutes (0.1 hour) – the standard in law firms and consulting. Precise and fair to both sides.
- 15 minutes (0.25 hour) – the most common for freelancers and agencies. A 32-minute call bills as 0.75 hours.
- 30 minutes or 1 hour – used for on-site visits and trades where a minimum call-out charge applies.
Rounding is normally applied per entry (per task or per day), not to the grand total. The calculator follows that convention and shows you exactly how much time rounding added, so you can see whether your policy is reasonable.
Tips for tracking billable time
- Track time as you go, not from memory at the end of the week – memory under-counts by 20–30%.
- Write a short description for each entry. Clients pay faster when the invoice tells them what the time was for.
- Decide in advance what is billable: meetings and revisions usually are; learning a new tool usually is not.
- Copy the task descriptions and decimal hours straight into the invoice generator as line items, with your hourly rate as the rate.
Not sure your rate is right? Check it with the hourly rate calculator.
Frequently asked questions
What is 1 hour 45 minutes in decimal?
1.75 hours. Divide the minutes by 60 (45 ÷ 60 = 0.75) and add the whole hours.
Is rounding billable time legal?
Yes, as long as it is reasonable, applied consistently and disclosed in your agreement or terms. Rounding every 2-minute email up to a full hour would not be considered reasonable.
Should I round up or to the nearest?
Most professionals round up to the next increment. Some round to the nearest increment, which averages out over time. Pick one, state it in your terms, and stick with it.
Do I bill for travel time?
It depends on your agreement. Many consultants bill travel at 50% of their rate or charge a flat call-out fee. State your policy in the quote before the work starts.