How to Calculate Billable Hours: A Complete Guide

What Are Billable Hours?

Billable hours are the time you spend working directly on client projects — the time you can charge for. They're different from total work hours, which include admin, emails, internal meetings, and other non-billable tasks.

The distinction matters because the two numbers are rarely close. If you work 40 hours a week but only bill 25, that gap is eating into your income — and you can't close a gap you've never measured.

The Basic Formula

Billable Amount = Billable Hours × Hourly Rate

Simple, but the tricky part is accurately tracking which hours are billable.

Step-by-Step Calculation

1. Track All Your Time

Before you can separate billable from non-billable, you need to track everything. For one week, log every task with start and end times. Include:

• Client project work (billable)
• Client meetings and calls (usually billable)
• Internal meetings (non-billable)
• Email and admin (non-billable)
• Business development (non-billable)

2. Categorize Each Entry

Mark each time entry as billable or non-billable. Some entries are obvious (coding for a client = billable). Others require judgment:

Activity	Typically Billable?
Client project work	Yes
Client meetings	Yes
Travel for client	Depends on contract
Research for project	Yes
Internal team meetings	No
Invoicing and admin	No
Proposals and pitches	No

3. Calculate Totals

Add up your billable hours per client, per project, or per day depending on how you bill.

Example:

Day	Total Hours	Billable	Non-Billable
Monday	8.0h	6.0h	2.0h
Tuesday	7.5h	5.5h	2.0h
Wednesday	8.0h	7.0h	1.0h
Thursday	8.5h	6.5h	2.0h
Friday	7.0h	4.5h	2.5h
Total	39.0h	29.5h	9.5h

Billable ratio: 29.5 / 39.0 = 75.6% — that's solid.

4. Apply Your Rate

29.5 hours × $85/hour = $2,507.50

5. Handle Overtime

If your contract includes overtime, hours beyond 8/day (or 40/week) are typically billed at 1.5x:

Regular: 29.5h × $85 = $2,507.50
Overtime: 2h × $127.50 = $255.00
Total: $2,762.50

Common Mistakes

1. Not tracking in real-time. Reconstructing your hours at the end of the week from memory means you'll undercount. Memory rounds down, and it rounds down in the client's favour, not yours.

2. Forgetting small tasks. A 15-minute client call is still 0.25 billable hours. Four of those per week = 1 hour you're giving away for free.

3. Rounding down. If your contract allows billing in 15-minute increments, a 20-minute task should be billed as 0.25h, not 0.33h. Know your rounding rules.

4. Not separating projects. If you work for multiple clients, track hours per client. Mixing them together makes invoicing a nightmare.

Tools That Help

Manual approach: Use our free timesheet calculator to add time entries, set your hourly rate, and see your billable total with overtime calculated automatically. No signup required.

Automated approach: If your billable work is already on your Google Calendar, Stintt pulls those events directly into a formatted timesheet. Use the Client Billing template to generate an invoice-ready export grouped by project.

Setting Your Billable Rate

Your hourly rate should account for non-billable time. If you want to earn $100K/year and can bill 1,500 hours (about 75% of 2,000 total hours):

$100,000 / 1,500 = $66.67/hour minimum

Most freelancers add a 20-30% buffer for taxes, insurance, and business costs, landing around $80-90/hour in this scenario.

Key Takeaway

Accurate billable hour tracking is the difference between getting paid fairly and leaving money on the table. Track in real-time, categorize honestly, and use tools that reduce the manual work. Your Friday afternoon self will thank you.