Enter one invoice's due date, the amount still owed and your daily late-fee rate to see how many days it is overdue, its aging status, the late fee so far and the total now owed. Days are whole calendar days in your own timezone, counted to the date shown on the result.
An unpaid invoice costs more the longer it sits. The Xuvilo invoice aging calculator tells you exactly where one invoice stands: enter its due date, the amount still owed and your daily late-fee rate, and it shows how many days the invoice is overdue, its aging status, the late fee so far and the total now owed.
Days are counted the way a person reads a calendar: whole calendar days from the due date to today, in your own timezone. An invoice due yesterday is one day overdue at any hour today, and an invoice due today is not overdue yet. The result shows the date it counted to, so anyone checking the figure can reproduce it.
The late fee is simple interest — amount × daily rate × days overdue — so 5,000 at 0.1% a day for 45 days adds 225. The calculator works on one invoice at a time with plain numbers, so the fee is in the invoice's own currency. Agree your late-fee rate in advance and state it on the invoice itself; the questions below explain why.
Days Overdue = Today − Due Date, in whole calendar days in your own timezone
Late Fee = Invoice Amount × Daily Rate ÷ 100 × Days Overdue
Total Owed = Invoice Amount + Late Fee
An invoice of $5,000 due on 1 January 2026 and checked on 15 February 2026 is 45 days overdue — seriously overdue. At 0.1% a day → late fee $225 → total owed $5,225.
As whole calendar days from the due date to today, in your own timezone — the date on your calendar, not a count of 24-hour periods. An invoice due yesterday is one day overdue at any hour today, and an invoice due today is not overdue yet. The result shows the date it was counted to.
Rates of 1.5% to 2% a month (about 0.05–0.067% a day) are common in business terms. Some jurisdictions cap late-payment interest and others set a default rate: for business-to-business invoices in the EU, the Late Payment Directive sets a statutory rate of the European Central Bank's reference rate plus at least 8 percentage points. In some countries, Saudi Arabia among them, courts may not enforce interest on late payment, so take local advice. Whatever you charge, state it on the original invoice.
Invoice aging (accounts receivable aging) groups outstanding invoices by how long they have been unpaid: 0–30 days, 31–60 days, 61–90 days, and 90+ days. An aging report helps businesses identify overdue accounts early, allocate collection effort, and calculate bad-debt provisions.
Best practice: send a friendly reminder 3–5 days before the due date, a polite follow-up on the due date, and increasingly firm reminders at 7, 14, and 30 days overdue. Early, regular reminders usually get invoices paid sooner. After 60 days or more, consider involving a collection agency.
In most jurisdictions, late fees must be agreed to in advance — either in your contract or clearly stated on the original invoice. Adding a late fee clause retrospectively is generally not enforceable. Include your payment terms and late fee rate on every invoice from the very first one.
DSO measures how many days on average it takes to collect payment: DSO = (Accounts Receivable ÷ Total Credit Revenue) × Number of Days. A rising DSO signals a cash flow risk. Aim to keep DSO close to your standard payment terms — around 30 days for customers on Net 30.
Set clear terms before the next invoice goes out with the payment terms guide, then issue it with the free Xuvilo invoice generator. More guides live on the Xuvilo Blog.
Open the free Invoice Aging Calculator now, or browse the full business calculator suite.
