A late payment fee is a charge applied to overdue invoices to compensate for delayed payment and encourage timely settlement. Whether you are a freelancer, small business owner, or accounts receivable manager, knowing exactly how much interest or penalty has accrued on an unpaid invoice is essential for cash flow management and professional communication with clients.
Invoice Details
Accrual Projections
| Period | Days Overdue | Late Fee | Total Due |
|---|
* Projections assume the same fee structure applied from the due date forward.
Sample Late Fee Clause
Calculation Breakdown
How to Calculate Late Payment Fees on Invoices
When clients pay invoices past the due date, you have the right to charge a late payment fee or interest to compensate for the delay and encourage prompt payment. This free late payment fee calculator helps you determine exactly how much is owed, whether you charge a flat fee, a monthly percentage, or daily accruing interest.
Step 1: Enter the Invoice Amount
Start by entering the original invoice amount in dollars. This is the principal balance on which late fees or interest will be calculated. Enter the full amount before any payments or credits have been applied.
Step 2: Set the Due Date and Payment Date
Enter the invoice due date and either the actual or expected payment date. You can also switch to "days overdue" mode if you already know how many days late the payment is. The calculator will compute the exact number of days overdue, minus any grace period you specify.
Step 3: Choose Your Fee Type
Select how you want to calculate the late fee. Percentage per month applies a monthly rate to the invoice amount for each month overdue (prorated for partial months). Daily interest uses an annual rate divided by 365 and multiplied by each overdue day. Flat fee charges a fixed one-time penalty regardless of how late the payment is.
Step 4: Configure the Grace Period
If your contract allows a grace period, enter the number of days. Late fees will not begin accruing until after the grace period expires. For example, with a 5-day grace period, an invoice paid 3 days late incurs no fee, while one paid 10 days late accrues fees for 5 days.
Step 5: Review Results and Projections
After clicking "Calculate Late Fee," you will see the total fee amount, the combined amount due (principal plus fee), the daily accrual rate, and projections at 30, 60, 90, 120, and 180 days. Use the sample contract language to include late fee terms in your future invoices and contracts. Always verify that your late fee rate complies with local regulations.
FAQ
Is this late payment fee calculator free?
Yes, this late payment fee calculator is completely free with no signup required. You can calculate overdue invoice fees as many times as you need. Everything runs in your browser, so your financial data stays private.
Is my data safe when using this tool?
Absolutely. All calculations run locally in your browser using client-side JavaScript. Your invoice amounts, dates, and fee details are never sent to any server. Nothing is stored or collected.
What is the difference between flat fee, percentage, and daily interest?
A flat fee is a fixed dollar amount charged once for any late payment. A percentage fee charges a percentage of the invoice total per month overdue. Daily interest calculates interest on the invoice amount for each day past due using an annual rate divided by 365.
How do I calculate daily interest on an overdue invoice?
To calculate daily interest, divide the annual interest rate by 365 to get the daily rate, then multiply by the invoice amount and the number of days overdue. For example, a $1,000 invoice at 12% annual rate accrues $0.33 per day in interest.
What is a grace period for late payment fees?
A grace period is a set number of days after the due date during which no late fee is charged. For example, a 5-day grace period means fees only start accruing on day 6 after the due date. Many businesses offer grace periods as a courtesy.
What is a typical late payment fee for invoices?
Common late payment fees range from 1% to 2% per month (12% to 24% annually). Many businesses charge a flat fee of $25 to $50 for smaller invoices. The maximum allowable rate varies by jurisdiction, so check your local laws before setting a rate.
Can I use the sample contract language from this tool?
The sample late fee clause provided is a general starting point for your payment terms. You should have a legal professional review your specific contract language to ensure it complies with local regulations and your business needs.