Free tool
Billable hours calculator
Billable hours are the hours of work you can charge a client for. To calculate them, add up the time spent on client work, round each entry to your billing increment, then multiply by the hourly rate. Paste your time below and the calculator does all three, plus write-downs, utilization and AI agent costs, entirely in your browser.
Billable amount = billable hours × hourly rate
Utilization = billable hours ÷ available hours
6 minutes = 0.1 hour · 15 minutes = 0.25 hour
Effective rate = amount invoiced ÷ all hours worked
Updated · By the Hourtick team
1. Paste or type your time
Toggl, Harvest or Clockify CSV, a spreadsheet, or one entry per line
2. Check the entries
- = 3:20 → 3:24
$595.00
- = 0:25 → 0:30
$87.50
- = 1:50 → 1:54
$285.00
- = 3:40 → 3:42
$555.00
- = 1:45 → 1:48
$315.00
- = 0:15
–
- = 1:30 → 1:30
$90.00
3. Rounding, rates and write-downs
4. Results
- Invoice total
- $1,927.50
- no write-down
- Billable hours
- 12.80
- 12:48 after rounding
- Rounding
- +0.30 h
- 6-min up, per entry
- Tracked
- 12.75 h
- 0.25 h not billable
- Effective hourly rate
- $171.33
- invoice ÷ all hours people worked
- Realization
- 100.0%
- billed ÷ standard value
- Utilization (net / gross)
- 68.8% / 70.3%
- 16.00 h available
- Missed vs target
- $150.59
- 1.00 billable h short of 75%
| Client | Tracked h | Billed h | Amount | AI agent cost | Margin |
|---|---|---|---|---|---|
| Acme | 5.50 | 5.70 | $997.50 | – | $997.50 |
| Northwind | 7.25 | 7.10 | $930.00 | $4.20 | $925.80 |
| Total | 12.75 | 12.80 | $1,927.50 | $4.20 | $1,923.30 |
| Person | Worked h | Billable h | Available h | Utilization |
|---|---|---|---|---|
| Maya | 5.58 | 5.58 | 8.00 | 69.8% |
| Leo | 5.67 | 5.42 | 8.00 | 67.7% |
| Team | 11.25 | 11.00 | 16.00 | 68.8% |
Track this automatically.Hourtick records billable time as you work, rounds it the same way and turns it into invoices. Free, no card.
Track this automaticallyWhat billable hours are
Billable hours are the part of your working time that a client pays for: design, writing, research, calls and travel when the contract allows it. Time spent on internal meetings, sales, admin or your own website is non-billable. Both are real work, so both belong in your timesheet; only billable hours go on the invoice.
Most firms bill in increments rather than exact minutes. Lawyers and accountants usually bill in 6-minute increments (tenths of an hour), consultants and agencies often in 15-minute increments (quarter hours). The increment is agreed with the client, normally in the engagement letter or contract.
The billable hours formula
Billable amount = billable hours × hourly rate. Billable hours are the rounded total of every billable entry.
Utilization = billable hours ÷ available hours × 100. Available hours are the hours a person could work in the period, for example 40 a week.
Effective hourly rate = amount invoiced ÷ all hours worked, billable or not. It shows what an hour of your time really earns.
Realization = amount invoiced ÷ standard value of the billable time. A write-down lowers realization; 100% means everything was billed at full rate.
How rounding works
Rounding converts tracked minutes into billable units. With 6-minute increments, 1 unit is 0.1 hour; with 15-minute increments, 1 unit is 0.25 hour. Rounding up bills any started unit in full: a 2-minute call becomes 0.1 hour. Rounding to the nearest unit is the most neutral, and rounding down favours the client.
You can round each entry or each day. Per-entry rounding is common in legal billing, where every task is a line on the bill. Per-day rounding adds up a person's time per client per day and rounds once, so many short entries don't each get rounded up. The calculator shows the difference as a separate rounding line, so it can be explained to a client.
A minimum charge, for example 15 minutes for any phone call, is applied after rounding: an entry is billed at least the minimum.
Billing increments in decimal hours
Every common billing increment, what one unit is in decimal hours, and who usually bills that way.
| Increment | One unit in hours | Common in |
|---|---|---|
| 1 minute | 0.0167 | Exact billing, software and support |
| 6 minutes | 0.1 | Lawyers, accountants (tenths of an hour) |
| 10 minutes | 0.1667 | Some consultancies (sixths of an hour) |
| 15 minutes | 0.25 | Agencies, consultants, IT services |
| 30 minutes | 0.5 | Coaching, trades, minimum call-outs |
6-minute increment chart
With 6-minute billing, each started block of 6 minutes is billed as a tenth of an hour when rounding up. 1 to 6 minutes is 0.1 hour, 7 to 12 minutes is 0.2 hour, and a full hour is 1.0.
| Minutes worked | Hours billed (rounded up) |
|---|---|
| 1–6 minutes | 0.1 |
| 7–12 minutes | 0.2 |
| 13–18 minutes | 0.3 |
| 19–24 minutes | 0.4 |
| 25–30 minutes | 0.5 |
| 31–36 minutes | 0.6 |
| 37–42 minutes | 0.7 |
| 43–48 minutes | 0.8 |
| 49–54 minutes | 0.9 |
| 55–60 minutes | 1.0 |
Worked examples
Legal, 6-minute increments rounded up: a lawyer at $300 an hour records a 0:25 call, a 1:52 draft and a 0:04 email. Rounded up to tenths these are 0.5, 1.9 and 0.1 hours: 2.5 billable hours, $750. Unrounded the time is 2.35 hours ($705), so rounding adds $45.
Consulting, 15-minute increments to the nearest quarter: a consultant at $180 an hour works 3:20 on a workshop and 0:40 on a follow-up. Rounded these become 3.25 and 0.75 hours: 4.0 hours, $720.
Agency, per-day rounding with a write-down: a designer logs four 10-minute fixes for one client on Monday, 40 minutes in total, at $150. Per-entry rounding to quarter hours would bill 1.0 hour; per-day rounding bills 0.75 hour, $112.50. A 10% goodwill write-down brings the invoice to $101.25 and realization to 90%.
Utilization for a team
Team utilization is total billable hours divided by total available hours, not the average of each person's percentage. If one person bills 30 of 40 hours (75%) and a part-timer bills 5 of 10 (50%), the team bills 35 of 50 hours: 70%, not 62.5%. The calculator sums the hours first, then divides.
Missed revenue compares billable hours with a target utilization. At a 75% target, 50 available hours should produce 37.5 billable hours; at 35 hours, the 2.5-hour gap times the average billed rate is the revenue left on the table.
AI agents next to people
If AI agents do client work, add their time as agent rows with the token or usage cost. Their hours can be billed at their own rate, they stay out of the team's utilization, and their cost is subtracted from each client's margin. Hourtick tracks agents this way automatically.
Your data stays in your browser
The calculator runs entirely on this page. Nothing you paste is uploaded. A share link stores the table in the part of the address after #, which browsers never send to a server.
Frequently asked questions
How do I calculate billable hours?
Add up the time spent on client work, round each entry (or each day) to your billing increment, and add the rounded entries together. Multiply by the hourly rate to get the amount to invoice.
What is a 6-minute increment?
One tenth of an hour (0.1 h). Firms that bill in 6-minute increments round every entry to a multiple of 6 minutes, so 1 to 6 minutes bills as 0.1 hour and 55 to 60 minutes as 1.0 hour when rounding up.
How many billable hours a year is normal?
It depends on the business. Many law firms target 1,600 to 2,000 billable hours a year per associate. Agencies and consultancies often aim for 60% to 80% utilization, which is about 1,100 to 1,500 hours for a full-time person.
Should I round per entry or per day?
Use what your contract says. Per-entry rounding is standard in legal billing; per-day rounding is fairer when there are many short entries, because each small task isn't rounded up separately.
What is the difference between utilization and realization?
Utilization is the share of available hours that were billable. Realization is the share of the billable time's standard value that was actually invoiced after write-downs.
Can I import time from Toggl, Harvest or Clockify?
Yes. Export a detailed report as CSV and paste it in. The calculator reads the date, person, client, description, duration, rate and billable columns. Rows it can't read are flagged and left out until you fix them.
Is the calculator free?
Yes, with no sign-up and no limits. Everything runs in your browser.
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Guides on billable hours
Hourtick for teams that bill by the hour
Stop adding up hours by hand.
Hourtick tracks billable time as you work, for people and AI agents, and turns it into invoices. Free for your whole team.