What a late-paying client actually costs
The financing cost of being paid 38 days late is $52. The chasing costs $198, and nobody invoices for that.
The short answer
Late payment costs more in time than in money. On a typical invoice the financing cost is small and the hours spent chasing are several times larger, which is why the effective fixes are structural, deposits and staged payments, rather than interest charges.
The formula
financing cost = invoice x annual rate x days late / 365
chasing cost = hours spent x your hourly rate
total cost = financing + chasing
as a share of the invoice = total / invoice
Chasing hours are billable hours you spent on admin. Costing them at zero is why late payment feels annoying rather than expensive.
Worked example
A $4,200 invoice on 30 day terms, paid on day 68, with two and a half hours spent chasing it at a $79 hourly rate:
days late = 68 - 30 = 38
financing at 12% = 4,200 x 0.12 x 38 / 365 = 52.47
chasing = 2.5 x 79 = 197.50
total = 249.97 → 5.95% of the invoice
across six invoices a year with the same client = 1,499.82
Nearly 6% of the invoice, and 79% of it is your time. A client who always pays at 68 days costs you about $1,500 a year in admin you never billed for.
Why interest charges rarely fix it
Statutory late payment interest exists in many countries and most freelancers never invoke it, because doing so risks the relationship and the amounts are small relative to the trouble.
It also arrives after the fact. The cost was the six weeks of uncertainty and the four emails, and a small interest payment afterwards does not return either.
It is still worth having in the contract. The threat is occasionally useful even when the charge is not, and having it there costs nothing.
The structural fixes that actually work
Deposits. A 40% deposit on the $4,200 invoice reduces the amount at risk to $2,520 and, more usefully, filters out clients who were never going to pay well.
Staged payments on longer projects, so no single balance grows large enough to be worth delaying.
Shorter terms stated plainly. Fourteen days is normal for small suppliers and many clients simply pay on whatever the invoice says without ever considering it.
And invoicing on the day the work is delivered rather than at month end, which alone removes an average of two weeks.
The client who is worth the trouble anyway
Some are. A client who pays at 68 days but provides steady, well-scoped, well-paid work may still be your best account, and the honest response is to price the delay in rather than to fight it.
The arithmetic makes that a decision instead of a resentment. If late payment costs 6% of the invoice, a 6% premium on that client's rate covers it and nobody has to have an awkward conversation.
What this leaves out
- The financing rate is illustrative. Use what borrowing actually costs you, or what the money would earn if you had it.
- Chasing hours vary enormously. Two and a half is typical for a client who eventually pays; a genuine bad debt costs far more.
- Excludes the knock-on cost of your own late payments to suppliers, which is where a payment delay does the most damage.
Common questions
- Should I charge late payment interest?
- Put it in the contract and use it rarely. Its value is mostly as a signal that you track this, and the real protection is deposits and shorter terms rather than the charge itself.
- What payment terms should a freelancer use?
- Fourteen days suits most small suppliers and many clients pay on whatever the invoice says. Larger organisations often have fixed cycles you cannot change, and knowing which kind of client you have before quoting matters more than the number.
- When should I stop working for a client who pays late?
- When the total cost, including your chasing time, exceeds what the work earns, or when a delay puts your own obligations at risk. Both are arithmetic rather than a feeling, which makes the decision easier to make and to explain.
Spreadsheets that do this
The formulas above, already built and checked — so you fill in your numbers rather than the arithmetic.
Related guides
Last reviewed 22 August 2026