How to Count Billable Working Days Between Two Dates
When a client contract runs from January 6 to March 28, how many days do you invoice for? The answer is not 81 — the total calendar days. It is the number of weekdays, Monday through Friday, that fall in that range. Invoicing for calendar days when your contract says working days is a common mistake that leads to client disputes and underpayment.
Why weekdays only
Standard freelance and consulting contracts bill for working days, not calendar days. Saturdays and Sundays are not included unless you have an explicit weekend clause in your contract. Most clients assume this without even stating it — which is why it matters to count correctly before you send the invoice.
The manual method
You could open a calendar and count every Monday through Friday between your start and end dates. That works for short ranges. For anything longer than two weeks, it gets error-prone fast.
There is a quick approximation: divide total calendar days by 7 to get full weeks, multiply by 5, then adjust for the partial week at each end. But edge cases — contracts starting on a Wednesday, ending on a Monday — make this tricky enough that a dedicated calculator is worth using.
What counts as a billable day
The default assumption is simple: any weekday (Monday–Friday) in the contract period is a billable day. That is what the Date Range Calculator on time2bill calculates.
Two things that are not automatically counted:
- Public holidays: These depend on your country, your client's country, and what your contract says. If your contract is silent, weekdays typically count regardless of public holidays.
- Days you were unavailable: If you took a week off mid-contract, subtract those days yourself before sending the invoice.
Handling partial months
A project that starts April 14 and ends April 30 has exactly the weekdays that fall within those 17 calendar days. You are not prorating a full month's rate — you are counting actual working days and multiplying by your day rate. This is cleaner and more defensible than any pro-rata calculation.
Use the calculator
Enter your start date, end date, and daily rate. The Date Range Calculator counts the weekdays automatically and returns the total invoice amount.
Count billable weekdays and calculate your invoice total instantly.
Open the Date Range CalculatorFrequently asked questions
Do I count the start and end dates as billable days?
It depends on your contract. Most contracts count both the first and last day if they fall on weekdays. The time2bill date range calculator includes both endpoints by default.
My project runs 6 weeks — how many billable days is that?
6 weeks × 5 weekdays = 30 billable days exactly, assuming the project runs Monday to Friday with no public holidays. Use the Date Range Calculator to confirm for specific dates.
How do I invoice for a partial week?
Count the individual weekdays in the range. A project running Wednesday to the following Tuesday covers 5 weekdays: Wednesday, Thursday, Friday, Monday, Tuesday.
What if my daily rate includes weekends?
That is unusual but possible. In that case, invoice for calendar days, not working days. Make sure your contract is explicit about this to avoid disputes.