How to use the retainer hours burn rate calculator
- Enter the hours in the retainer and the hours used so far.
- Set the period start, the period end and the as of date for the hours used.
- Choose whether to count every day or weekdays only, and add an overage rate if you want to see the cost.
- Read the share used against the share of the period gone, the projected total and the hours you can still use each day.
Formula
Share of period gone = days elapsed / days in the period
Even pace = retainer hours x share of period gone
Projected use = hours used / days elapsed x days in the period
Hours per day left = (retainer hours - hours used) / days remaining
Days are counted from the start date through the as-of date, inclusive. In weekday mode, Saturdays and Sundays are skipped in every count.
40 hours, 28 used by October 15
In a period from October 1 to October 31, 2026, with 40 retainer hours and 28 used by October 15, counting every day: 15 of 31 days have gone (48.4 percent) and 70 percent of the hours are used. The even pace is 19.35 hours, so you are 8.65 hours ahead. At this pace the projected use is 57.87 hours, 17.87 hours over, and 0.75 hours a day are left for the 16 remaining days.
Counting weekdays only, 11 of 22 weekdays have gone (50 percent), the projection is exactly 56 hours and 1.09 hours a day are left. At an overage rate of $120 an hour the projected overage is 16 hours, or $1,920.00.
Using the projection
A projection is a straight-line guess: it assumes the next days look like the days so far. It works well as an early warning. If it shows you running out in the middle of the period, raise it with the client while there is still time to adjust the work, the scope or the retainer. If work arrives in bursts, check the projection again after each burst.
For setting a retainer see the retainer fee calculator and the freelance rate calculator. A deadline counted in business hours is in the business hours deadline calculator, and your net pay per hour in the true hourly wage calculator.
Calendar days or weekdays
If you work only on weekdays, counting every day makes the period look longer than it is and understates the burn rate. Weekday mode counts Monday to Friday only, and it does not know about public holidays or your own days off. If those matter, shorten the period or adjust the end date by hand.
Assumptions and limits
- The period has a start date and an end date, and the as-of date is inside it.
- Use continues at the average pace so far; holidays and unusual weeks are not predicted.
- In weekday mode only Monday to Friday count, and holidays are not removed.
- The overage cost is the projected extra hours times the rate you enter, with no other terms.
Frequently asked questions
How do I calculate retainer burn rate?
Divide the hours used by the days elapsed, then multiply by the days in the period for the projected total. Compare it with the retainer hours.
How many hours can I use per day for the rest of the period?
Divide the hours left by the days remaining. With 12 hours left and 16 days it is 0.75 hours a day.
What does ahead of pace mean?
It means you have used more hours than an even spread over the days so far would give. If it continues, the retainer runs out before the period ends.
Does unused time carry over?
That depends on your agreement. The page looks at one period only and does not model rollover or expiry.