Billable Hours Calculator
A billable hours calculator totals the time you spend on client work, rounds it to your billing increment (such as 6 or 15 minutes), and multiplies it by your hourly rate to show what you can bill.
Billable amount = billable hours × hourly rate
Billable hours calculator
Calculate billable amount from hours
Enter the time worked, your rate and your billing increment.
Your result
- Time worked
- Billed time
- Billed decimal hours
- Effect of rounding
Add up billable time from start and end times
Uses 24-hour (military) time or AM/PM, depending on your browser. If the end time is earlier than the start time, the calculator assumes the work passed midnight.
Billable utilization and effective hourly rate
See how much of your working time you actually bill, and what each working hour earns.
Your result
- Non-billable hours
- Billable revenue
- Effective hourly rate
Utilization = billable hours ÷ total hours worked. Effective rate = billable revenue ÷ total hours worked.
Turn an annual target into weekly and daily hours
Enter a revenue goal, or type a billable-hours target to override it.
Your result
- Hours per month
- Hours per week
- Hours per working day
- Projected revenue
Hours needed = revenue goal ÷ hourly rate.
Billable hours formula
Billable amount = billable hours × hourly rate. To get billable hours in decimal form, divide your billed minutes by 60.
- Billable hours are hours spent directly on client work, excluding internal meetings, admin and breaks.
- Billing increment is the block your time is rounded to. Law firms and accountants commonly use 6 minutes (0.1 hour); many consultants and agencies use 15 minutes (0.25 hour).
- Hourly rate is what you charge the client for each billable hour.
Example: 1 hour 53 minutes of work, 6-minute increments rounded up, $150 per hour.
113 minutes rounds up to 114 minutes. 114 ÷ 60 = 1.9 billable hours. 1.9 × $150 = $285.00.
How to calculate billable hours
- Record the time. Note start and end times for each task, or the total minutes spent.
- Remove non-billable time. Subtract breaks, internal meetings and admin.
- Round to your billing increment. Use the increment in your contract, such as 6 or 15 minutes, and round up, down or to the nearest block.
- Convert to decimal hours. Divide the rounded minutes by 60.
- Multiply by your rate. Billable hours × hourly rate gives the amount to invoice.
Worked example with three tasks, 6-minute increments rounded up, $150 per hour:
47 min → 48 min (0.8 h). 82 min → 84 min (1.4 h). 125 min → 126 min (2.1 h).
Total: 0.8 + 1.4 + 2.1 = 4.3 billable hours × $150 = $645.00. Exact time was 4.23 hours ($635.00), so rounding added $10.00.
Use the start and end times tab to do this for a full day of entries.
Billing increments: 6-minute and 15-minute rounding
Rounding to an increment keeps invoices tidy and makes short tasks billable. Check your engagement letter or contract, because some clients cap rounding or require rounding to the nearest increment rather than up.
| Minutes worked | Billed hours |
|---|---|
| 1–6 | 0.1 |
| 7–12 | 0.2 |
| 13–18 | 0.3 |
| 19–24 | 0.4 |
| 25–30 | 0.5 |
| 31–36 | 0.6 |
| 37–42 | 0.7 |
| 43–48 | 0.8 |
| 49–54 | 0.9 |
| 55–60 | 1.0 |
| Minutes worked | Billed hours |
|---|---|
| 1–15 | 0.25 |
| 16–30 | 0.50 |
| 31–45 | 0.75 |
| 46–60 | 1.00 |
Both tables show rounding up. If you round to the nearest increment instead, 1–2 minutes would bill as 0 in a 6-minute system, so most firms set a minimum of one increment per task.
Minutes to decimal hours chart
Exact conversion is minutes ÷ 60. Use this chart for timesheets and invoices that need decimal hours without rounding to an increment.
| Minutes | Decimal hours | Minutes | Decimal hours |
|---|---|---|---|
| 5 | 0.08 | 35 | 0.58 |
| 10 | 0.17 | 40 | 0.67 |
| 15 | 0.25 | 45 | 0.75 |
| 20 | 0.33 | 50 | 0.83 |
| 25 | 0.42 | 55 | 0.92 |
| 30 | 0.50 | 60 | 1.00 |
How lawyers calculate billable hours
Most law firms record time in 6-minute increments, where each increment is 0.1 hour, then multiply the total tenths by the attorney’s hourly rate.
A 20-minute client call is billed as 0.4 hours (19–24 minutes). At $350 per hour that is 0.4 × $350 = $140. Entries for the day are added together, and many firms also set annual billable-hour targets for associates. Targets differ by firm, so confirm yours in your employment terms.
Accountants, consultants and agencies often use the same method or switch to 15-minute blocks. Whichever you use, apply it consistently and state it in your contract.
How to calculate your billable hourly rate
Billable hourly rate = (target annual income + annual business expenses) ÷ annual billable hours.
The key input is realistic billable hours. Few people bill every working hour, because time goes to admin, sales, learning and time off.
Example: You want to earn $90,000 and expect $15,000 in business expenses.
Working weeks: 48. Hours per week: 40. Total hours: 1,920. If 65% is billable: 1,920 × 0.65 = 1,248 billable hours.
Rate = ($90,000 + $15,000) ÷ 1,248 = $84.13 per hour.
To work backwards from a revenue goal to weekly and daily hours, use the annual target tab.
Billable vs non-billable hours
| Billable hours | Non-billable hours |
|---|---|
| Client calls and meetings | Internal meetings |
| Research, drafting, design, development for a client | Admin, bookkeeping and invoicing |
| Project management on a client project | Marketing and business development |
| Travel, if your contract allows billing it | Training, breaks and time off |
Utilization rate
Utilization rate = billable hours ÷ total hours worked × 100.
If you work 40 hours and bill 28, your utilization rate is 70%. At $100 per hour you earn $2,800, but your effective hourly rate across all 40 hours is $70. Many service businesses aim for roughly 60% to 80%, though the right target depends on your role, costs and pricing. Try your own numbers in the utilization tab.
Calculating billable hours with military time
Military (24-hour) time removes AM/PM confusion. Subtract the start time from the end time, then subtract any break.
Example: 09:30 to 13:45 with a 15-minute break.
13:45 − 09:30 = 4 h 15 min. Minus 15 min break = 4 h 00 min = 4.0 decimal hours.
If the end time is earlier than the start time, the work passed midnight: add 24 hours to the end time first. For example, 22:00 to 02:30 is 4 hours 30 minutes, or 4.5 hours.
Billable hours calculator FAQ
How do you calculate billable hours?
Add up the time you spent directly on client work, excluding internal meetings, admin and breaks. Round it using your billing increment, convert to decimal hours by dividing minutes by 60, then multiply by your hourly rate to get the billable amount.
What is the formula for billable hours?
Billable amount = billable hours × hourly rate. Billable hours in decimal form = billed minutes ÷ 60. For example, 114 billed minutes is 1.9 hours, and at $150 per hour that bills $285.
How do lawyers calculate billable hours?
Most law firms track time in 6-minute increments, where each increment equals 0.1 hour. Up to 6 minutes is billed as 0.1, 7 to 12 minutes as 0.2, and so on. The total tenths are added up and multiplied by the attorney’s hourly rate.
How are billable hours calculated in 15-minute increments?
Time is rounded to 0.25-hour blocks: 1 to 15 minutes is 0.25 hour, 16 to 30 minutes is 0.5, 31 to 45 minutes is 0.75 and 46 to 60 minutes is 1.0 hour.
How do I calculate my billable hourly rate?
Billable hourly rate = (target annual income + annual business expenses) ÷ annual billable hours. For example, ($90,000 + $15,000) ÷ 1,248 billable hours = $84.13 per hour. Use a realistic billable hour count, since most people cannot bill 100% of their working time.
How do I convert minutes to decimal hours for billing?
Divide the minutes by 60. 15 minutes is 0.25 hours, 30 minutes is 0.5, 45 minutes is 0.75 and 20 minutes is 0.33. For 6-minute billing, divide the rounded minutes by 60, so 18 minutes is 0.3 hours.
What counts as billable hours?
Billable hours are hours spent on work you can charge a client for, such as client calls, research, drafting, design, development and project meetings. Non-billable hours include internal meetings, admin, marketing, training, invoicing and breaks, unless your contract says otherwise.
How do I calculate billable hours using military time?
Subtract the 24-hour start time from the end time, then subtract breaks. For example, 09:30 to 13:45 is 4 hours 15 minutes, or 4.25 decimal hours. If the end time is earlier than the start time, add 24 hours because the shift passed midnight.
What is a good billable utilization rate?
Utilization rate = billable hours ÷ total hours worked × 100. Targets vary by role and firm. Many service businesses aim for roughly 60% to 80%, but you should set the target from your own costs and pricing.
Can Desklog track billable hours automatically?
Yes. Desklog tracks time against projects and tasks, separates billable and non-billable hours, supports project timesheets, and connects recorded hours with project billing and invoicing. Desklog also offers a free plan for up to 3 users with unlimited projects.
This calculator provides estimates for general guidance. Check your contract or engagement letter for the rounding and billing rules that apply to your work.