Late Payment Fee Calculator

A late payment fee calculator works out the late fee on an overdue invoice from the invoice amount, a monthly late fee rate (applied per day as rate ÷ 30) and the days overdue, and shows the total amount now due.

This calculator gives you the exact late fee and total now due on an overdue invoice: enter the invoice amount, the agreed monthly rate, and days overdue. Most invoices and contracts specify a late payment charge — commonly 1.5-2% per month — but almost nobody actually calculates what that amounts to for a specific overdue amount and number of days late.

The calculation converts your monthly rate to a daily rate (monthly rate ÷ 30) and applies it per day overdue — a simple, defensible method that matches how most late-fee clauses are actually worded. This makes the number concrete rather than abstract when you're following up on late payment, which strengthens a payment reminder considerably: "the late fee is currently ₹1,167 and grows daily" lands harder than a vague mention of penalties.

Before charging a late fee, confirm your invoice or contract actually specifies one — charging a fee that wasn't agreed upfront is legally shaky and damages the relationship. If you haven't been including a late-fee clause, add one to future invoices and contracts so this calculator has real teeth going forward.

Recalculate as the overdue period grows rather than quoting a stale figure from the first reminder — the fee compounds daily under most clause wordings, so a number quoted three weeks ago understates what's actually owed today. Keeping the figure current also signals to the customer that you're tracking the account closely.