Invoice Late Payment Calculator
Work out how many days an invoice is overdue, estimate a late payment fee and total amount owing, and generate a reminder message to send to your client.
This is a general estimate tool only. It does not confirm whether a late fee is enforceable under your invoice terms or applicable law.
Invoice Late Payment Calculator
Enter the invoice amount, due date, current date and a monthly late fee rate to estimate the days overdue, late fee and total amount owing.
Results
What this calculator helps with
Use this tool when you want a quick view of an overdue invoice before following up with a client.
See how many days have passed since the invoice due date.
Estimate a late payment fee using a simple daily rate.
See the invoice amount plus the estimated late fee combined.
Generate a friendly reminder message you can send to your client.
How to Use This Calculator
- Enter your business name and the client's name.
- Enter the invoice amount and the monthly late fee rate you want to apply.
- Select the invoice due date and the current date.
- Add an optional custom note if you want to personalise the reminder message.
- Click calculate to see the days overdue, estimated late fee and total amount owing.
- Copy the generated reminder message to send to your client.
The calculator gives you a simple estimate. Before charging a late fee, check your invoice terms, any signed contract, and whether the fee structure is appropriate for your business and client relationship.
What to Check Before Chasing an Overdue Invoice
A late fee estimate can help with planning a follow-up, but the right approach depends on your invoice terms, your relationship with the client, and how far overdue the payment is.
- Check your invoice terms for any stated late payment fee or interest clause
- Confirm the invoice was received and there is no dispute over the amount or work
- Keep a record of reminders sent and dates followed up
- Consider a phone call for larger or long-overdue amounts rather than email alone
- Review your bookkeeping records so overdue invoices are easy to track going forward
If overdue invoices keep affecting your cash flow, the bigger issue is often the invoicing and bookkeeping process behind it. Our bookkeeping services can help keep your records and follow-ups organised.
When to Speak With an Accountant About Cash Flow
If overdue invoices are becoming a regular pattern, the next step is usually to review your bookkeeping and invoicing process rather than just chasing individual payments.
True Ledger Accounting can help with bookkeeping services, small business accounting support and business advisory to improve cash flow visibility.
Or if you want help reviewing your invoicing and cash flow process, contact us here.
Frequently Asked Questions
How does this calculator estimate a late payment fee?
It applies a simple daily rate to the invoice amount based on the monthly late fee percentage you enter (monthly rate ÷ 100 ÷ 30), multiplied by the number of days the invoice has been overdue.
Can I legally charge a late payment fee?
This depends on your invoice terms, any contract in place, and applicable Australian consumer and contract law. This calculator provides an estimate only and does not confirm whether a late fee is enforceable in your situation.
What if the invoice is not overdue yet?
The calculator will show the invoice as not overdue and estimate a $0.00 late fee. You can still use the reminder message field to prepare a friendly note ahead of the due date.
Does this calculator send the reminder to my client?
No. It generates reminder text you can copy and paste into an email or message yourself. Nothing is sent automatically.
Can True Ledger Accounting help with overdue invoices and cash flow?
Yes. True Ledger Accounting can help Melbourne businesses with bookkeeping, invoicing processes and cash flow visibility so overdue payments are easier to track and follow up.
Need Help With Cash Flow or Overdue Invoices?
Use the calculator for a quick estimate, then get your bookkeeping and invoicing process reviewed to reduce overdue payments.
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