How to add late fees to your next invoice
- Put it in writing first. A late fee clause should be in your contract or invoice terms before you can charge it.
- Pick a clear policy. Common: 1.5% per month or the maximum statutory rate in your state, whichever is lower.
- Send a written notice. Most states require you to notify the customer that interest is accruing.
- Apply it consistently. Pick a rule and stick to it for every overdue invoice — selective enforcement makes future disputes harder.