Payment Terms & Late Payments
Late Payment Interest Calculator
Calculate interest on an overdue invoice from dates or days, with annual or monthly rates and simple, monthly or daily compounding.
Result
Days overdue
0 days
Interest per day
$0.33
Interest
$0.00
As % of the original amount
0%
Total due
$1,000.00
How it's calculated
Simple interest = amount × annual rate × days ÷ 365 (or 360). A monthly rate is converted to annual × 12. Compound interest adds interest to the balance monthly or daily: amount × ((1 + rate per period)^periods − 1).