Some clients pay a decent monthly amount but eat so many hours in calls, revisions and admin that the real hourly rate is far below what you charge anyone else. This calculator puts a number on that, then checks whether replacing the client would actually pay off once you allow for the time it takes to find new work and the chance you won't fill every hour.
How it works
Your real rate with this client is their monthly revenue divided by every hour they take, including unbilled communication. That's the number to compare with your target rate.
The best case assumes every freed hour is resold at your target rate. The realistic case multiplies that by the share of hours you expect to refill, because few freelancers replace 100% of freed time straight away.
Replacing a client isn't free. While you look for new work you lose their revenue, so the transition loss is their monthly revenue times the months it takes. The payback period divides that loss by the realistic monthly gain.
The stress score doesn't change the math. It's there because a client who drains you also costs energy and focus on your other work, and that belongs in the decision even if it doesn't show up in the numbers.
A worked example
A client pays $1,200 a month but takes 40 hours, so they really pay $30 an hour. Your target is $60. If you could refill 75% of those hours, you'd earn 40 × 0.75 × $60 = $1,800, a realistic gain of $600 a month. Two months without their income costs $2,400, which the extra $600 a month earns back in 4 months.
Questions people ask
How do I know if a client is worth keeping?
Divide what they pay each month by every hour they take, including calls and emails. If that rate is well below what your other clients pay, and you could realistically fill the time, they're costing you money. Stress and scope creep count too.
Should I raise the rate before firing the client?
Often, yes. A rate increase to your target either fixes the problem or makes the decision for you. Give reasonable notice and explain the change as part of a general price review.
What refill rate should I assume?
Base it on your pipeline. With a waiting list, 90% or more is realistic. If you'd be starting from scratch, 50 to 75% is safer. When unsure, run the calculator at a few refill rates to see where replacing the client stops paying off.
How do I end a client relationship professionally?
Give the notice period in your contract, finish or hand over work in progress, and offer a referral if you can. Keep the message short and neutral. You don't need to list every complaint.
Why count hours I don't bill?
Because those hours could be sold to someone else. Unbilled calls, revision rounds and chasing payments are part of what the client costs you, even if they never appear on an invoice.