How an hourly invoice works
An hourly invoice is a normal invoice where each line is time instead of a product. The quantity is the number of hours, the price is your hourly rate, and the line amount is the two multiplied. Add a line for every day or every task, and the total is your pay for the period.
The hours can be fractions. Type 1.75 for an hour and three quarters, or 0.5 for a half hour, and the amount is worked out to the cent. If you bill different rates for different kinds of work, give each rate its own line instead of averaging them.
Converting minutes to decimal hours
Timers and calendars show hours and minutes, but an invoice needs a decimal number. Divide the minutes by 60:
| Time worked | Decimal hours | At $85/hr |
|---|---|---|
| 15 min | 0.25 | $21.25 |
| 30 min | 0.5 | $42.50 |
| 45 min | 0.75 | $63.75 |
| 1 h 10 min | 1.17 | $99.45 |
| 1 h 20 min | 1.33 | $113.05 |
| 2 h 40 min | 2.67 | $226.95 |
A common mistake is typing 1.20 for "one hour twenty". That's 1 hour and 12 minutes, so you'd undercharge by 8 minutes on every such line. Many people avoid odd decimals by billing in set increments, which is the next decision.
Increments, minimums and premium rates
Decide these rules once, write them in the notes, and apply them the same way every time:
- Billing increment. Quarter hours (0.25) are the most common for trades, IT and admin work. Lawyers and accountants often use tenths (6 minutes). Say whether you round up or to the nearest increment.
- Minimum charge. A one-hour minimum for a site visit or a 15-minute minimum for a phone call covers the time you spend getting started.
- After-hours rate. Evenings, weekends and holidays often run 1.5 times the normal rate. Put them on separate lines so the client sees exactly which hours cost more.
- Travel time. Some bill it at full rate, some at a reduced rate, some not at all. Whatever you choose, show it as its own line.
Not sure what to charge? The hourly rate calculator works back from the income you want to a rate per hour.
Make the hours easy to approve
Clients rarely argue with a rate they agreed to. They argue with hours they can't picture. A few habits help:
- Date every line and say what was done, in words the client would use. "Oct 8: Wi-Fi dropouts in operatory 2" is easy to approve. "Support, 1.75 h" is not.
- Bill on a fixed cycle, weekly or every two weeks. A month of hours in one total looks bigger than four small invoices and is harder to check.
- Keep the timesheet from your timer app or notebook, and offer it in the notes. Most clients never ask, but knowing they could helps.
- List materials and expenses separately from labor, so the hourly total stays honest.
- Put the period in the reference field, such as "Timesheet Oct 6–17", so nothing gets billed twice.
Hourly or fixed price?
Hourly billing is fair when the work is hard to size in advance: troubleshooting, on-call support, ongoing admin, repairs where you don't know what you'll find. The client pays for exactly the time used, and you aren't punished when a job runs long.
It works less well when the client needs a firm budget before saying yes. In that case send an estimate with your expected hours, or switch to a flat price and use a project-style freelance invoice. Consultants who mix hourly, day-rate and retainer work will find more on the consulting invoice page.
Last checked October 23, 2026.