How to Calculate Late Fees on Invoices

Late payments cost freelancers thousands of dollars in lost productivity and cash-flow stress each year. Charging late fees is not just about recovering losses — it incentivizes clients to pay on time.

Standard Late Fee Rates

The most common late fee rate is 1.5% per month on the outstanding balance (which equals 18% annually). Some freelancers charge a flat fee of $25–$50 for invoices under $1,000, or 1–2% per month for larger amounts.

How to Calculate a Monthly Late Fee

To calculate a 1.5% monthly late fee: multiply the overdue amount by 0.015. For example, on a $2,000 overdue invoice: $2,000 × 0.015 = $30 late fee for the first month. If it remains unpaid for two months, the second month's fee applies to the new balance of $2,030.

State-by-State Regulations

Most US states allow late fees but cap the maximum rate. For example, California caps interest at 10% annually, while Texas allows up to 18% annually. Check your state's laws before setting your rate. In practice, 1.5% per month (18% annually) is legal in most states.

How to Word Your Late Fee Policy

Include your late fee terms clearly on every invoice: 'Payment is due within 30 days of invoice date. A 1.5% monthly late fee (18% APR) will be applied to all balances overdue by more than 7 days.' This sets expectations upfront and gives you legal standing to charge the fee.

When to Enforce Late Fees

Many freelancers waive late fees for first-time offenders or long-term clients who pay late once. Be consistent with clients who habitually pay late — enforcing the fee or requiring upfront deposits for future work sends a clear message.