Online Receipt Generator
Payment Terms & Late Payments

Days Past Due Calculator

See how many calendar and business days an invoice is past due, and which aging bucket it falls into.

Result

Days past due

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Business days past due

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Days until due

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Aging bucket

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Embed this calculator on your site

Copy this code and paste it into your page's HTML. The calculator is free to use and resizes itself to fit.

How it's calculated

Days past due = as-of date − due date (0 if not due yet). Business days skip weekends. The aging bucket follows the standard 1–30 / 31–60 / 61–90 / 90+ grouping used in receivables reports.

This days past due calculator shows how overdue an invoice is on a chosen date. It returns calendar days, business days and the aging bucket. If the invoice is not due yet, it shows the days until due.

The formula

days past due          = as-of date - due date          (0 if not due yet)
days until due         = due date - as-of date          (0 if overdue)
business days past due = weekdays after the due date, up to the as-of date

Aging buckets: current (not overdue), 1-30, 31-60, 61-90 and 90+ days.

Worked example

Due date 2026-02-15. As-of date 2026-04-01.

  • Days past due: 45
  • Business days past due: 33
  • Aging bucket: 31-60 days

The 12 non-business days are the weekend days between the two dates.

How to read the result

The bucket tells you what action fits. A 1-30 invoice needs a polite reminder. A 31-60 invoice needs a call or a firm letter. Older invoices need a payment plan or a formal step.

Older invoices are less likely to be paid in full. Move quickly in the early buckets.

Use the as-of date to look back or forward. Set it to the end of a month to see where an invoice will stand in your month-end report.

Business days past due show how many working days you gave the customer after the due date. Public holidays are not removed.

Rules on interest, fees and legal steps depend on your country and your contract. Check them with an accountant or a legal adviser before you act.

Related tools

Frequently asked questions

How do I calculate days past due?
Subtract the due date from the as-of date. An invoice due on 15 February 2026 is 45 days past due on 1 April 2026. If the result is zero or less, the invoice is not past due.
What are aging buckets?
Buckets group overdue invoices by age. The usual groups are current, 1-30, 31-60, 61-90 and 90+ days. Accountants use them in an accounts receivable aging report.
Do days past due start on the due date?
No. The due date itself is day zero. The first past-due day is the day after. An invoice paid on its due date is not late.
What is the difference between calendar and business days past due?
Calendar days count every day. Business days skip Saturdays and Sundays. Public holidays are not excluded here. Contracts and collection letters usually use calendar days.
When should I start collection steps?
Send a friendly reminder soon after the due date. Escalate in steps as the invoice moves into older buckets. Match your steps to your terms and local rules.