Free late fee calculator
Calculate an overdue invoice balance.
See the days overdue, one-time late fee, and updated amount due. Nothing is stored or sent.
Invoice and fee details
Updated balance
$1,000.00
- Original invoice
- $1,000.00
- Days overdue
- 0
- One-time late fee
- $0.00
This is an informational estimate, not legal or tax advice. Confirm that your contract and local rules allow the fee before charging it.
Frequently asked questions
How is the late fee calculated?
Choose either one fixed fee or one percentage of the original invoice amount. The calculator applies it once after the due date and grace period.
Does this calculator compound fees?
No. It never adds interest to a previous fee and does not repeat a charge monthly. The result is a single, transparent late fee.
Can I charge any late fee I choose?
Not necessarily. Contracts and local laws may limit late fees or require advance disclosure. Treat this result as an estimate and check the rules that apply to you.