Invoice Late Fee & Interest Calculator
Calculate daily and total late-payment interest plus flat administrative fees on overdue client invoices.
Calculator Inputs
Updates automaticallyQuick Reference Table
| Invoice | Annual Rate | 30 Days Interest |
|---|---|---|
| $1,000 | 12% (1%/mo) | $9.86 |
| $1,500 | 18% (1.5%/mo) | $22.19 |
| $5,000 | 18% (1.5%/mo) | $73.97 |
Frequently Asked Questions
Can I charge late fees without mentioning them upfront?
Always include your late-payment terms (e.g., 1.5% monthly interest after Net-15) in your contract and invoice footer.
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