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Late Payment Interest Calculator
Enter the rate that applies to your contract or jurisdiction. The calculator shows daily interest, total interest and the full amount owed including fixed compensation.
The rate and any fixed compensation must come from the contract or the applicable statute. This is arithmetic, not legal advice.
A payment term without a consequence is a request
Net 30 describes when a client should pay; it does not describe what happens when they do not. Interest and fixed compensation turn the term into a priced consequence. Even when the clause is never invoked, it changes the conversation about a late invoice because the amount owed is no longer ambiguous.
Check the lawful rate and any compensation rule in the client's jurisdiction before drafting. Some regimes set a statutory reference rate and a fixed sum; others require the contract to specify the rate.
Interest is rarely the whole loss
On a 5,000 invoice at eight percent, a 45-day delay accrues about 49 in interest. That is small relative to the cash-flow problem: the freelancer may have to fund the month from savings or decline another project. The clause should be paired with a deposit, milestone billing or a stop-work right, because interest compensates the delay but does not prevent it.
Frequently asked questions
Simple or compound interest?
This calculator uses simple interest, which is the usual basis for statutory late-payment interest. A contract can specify compounding, but then the calculation must follow the contract.
What is fixed compensation?
A flat sum some jurisdictions allow on top of interest to cover the cost of chasing the payment. Enter zero if your contract or jurisdiction does not provide one.
When does interest start?
Usually the day after the agreed payment date, but the trigger depends on the contract and the law. Enter the days from that trigger to today.
Can I charge interest retroactively?
Only if the contract or the law supports it. Adding a clause after the invoice is issued does not normally apply to that invoice.