⏰ Invoice Late Fee Calculator
A late invoice is an interest-free loan you never agreed to make. If your terms include a late fee (they should), here is exactly what to add, prorated by the day, so the number on your reminder email is precise instead of awkward.
1 to 2 percent per month is the common range. It must be stated in your contract or invoice terms to be chargeable.
Late fee to add
$37.5
Updated invoice total
$2,538
What each additional day costs them
$1.25
Your $2,500 invoice is 30 days late. At 1.5 percent per month that is a $38 late fee, making the new total $2,538, and it grows $1 every additional day. Put those exact numbers in your reminder; specific beats apologetic every time.
Estimates for planning, not financial advice. Your real numbers will vary; that is exactly why you track them.
Does this resonate?
Chronic late payers are a pricing and positioning signal
The clients who pay late are usually the ones who negotiated hardest. Check whether your rate is attracting the wrong clients in the first place.
Check what you should be charging →Good questions about this math
How much can I legally charge as a late fee?
It must be in your agreed terms (contract or accepted invoice terms), and many US states cap interest-style fees, commonly in the neighborhood of 10 to 18 percent per year (about 0.8 to 1.5 percent per month). The standard practice of 1 to 1.5 percent monthly fits most caps, but check your state before going higher.
How is the fee calculated?
The common convention, and the one used here, is simple prorated interest: invoice amount times the monthly rate, times days late divided by 30. Some businesses charge a flat fee instead; a percentage scales fairly across invoice sizes.
Do late fees actually get paid?
Often the fee's real job is prevention: clients who know a fee is real pay faster. Many freelancers waive the first fee as a courtesy while making clear it applies going forward. The worst move is having no fee at all, which trains slow payers that late is free.
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