What does days past due mean?

Days past due is the number of calendar days since an invoice’s due date. If payment was due August 1 and you check on August 31, the invoice is 30 days past due.

How do I calculate days past due?

Subtract the invoice due date from the calculation date using calendar days. If the due date has not arrived, the invoice is not yet overdue.

What are the standard invoice aging buckets?

Common AR aging buckets are Current / Not Due, 1–30 days, 31–60 days, 61–90 days, and 90+ days. This calculator uses those ranges.

Is 30 days overdue in the 1–30 or 31–60 bucket?

30 days overdue is in the 1–30 bucket. 31 days overdue begins the 31–60 bucket.

Does this calculator use business days?

No. Days past due and aging buckets use calendar days, including weekends and holidays. Use the Business Days Calculator when you need working-day math.

Why do businesses track overdue invoices?

Aging overdue invoices helps prioritize collections, spot customers who pay late, and see whether old receivables are growing.

Days Past Due Calculator

Enter an invoice due date to see how many calendar days it is overdue and which accounts receivable aging bucket it falls into.

Aging result

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Enter a due date to calculate.

Days past due: —
Aging status: —
Aging bucket: —
Outstanding balance: —

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What “days past due” means

Days past due measures how long an invoice has remained unpaid after its due date. It is a calendar-day count: weekends and holidays are included unless your terms say otherwise.

If the due date is today, the invoice is due today—0 days past due. If the due date is still in the future, the invoice is not yet overdue.

How to calculate days past due

Days past due = Calculation date − Invoice due date

Due date August 1, check on August 31 → 30 days past due
Due date August 31, check on August 31 → Due today (0 days)
Due date September 15, check on August 31 → Not yet overdue (15 days remaining)

Common invoice aging buckets

Accounts receivable aging groups overdue balances by how long they have been past due. This calculator uses the same buckets as the AR Aging Calculator:

Current / Not Due: The due date has not passed, or the invoice is due today (0 days past due).
1–30 days: 1 through 30 calendar days overdue.
31–60 days: 31 through 60 calendar days overdue.
61–90 days: 61 through 90 calendar days overdue.
90+ days: 91 or more calendar days overdue.

Why businesses track overdue invoices

Prioritize collection follow-up on the oldest balances
See whether late payments are concentrated with specific customers
Decide when to send reminders, apply late fees, or escalate
Monitor whether aging risk is increasing over time

Worked examples

Due date	As of	Result	Bucket
Sep 15, 2026	Aug 31, 2026	Not yet overdue · 15 days remaining	Current / Not Due
Aug 31, 2026	Aug 31, 2026	Due today · 0 days past due	Current / Not Due
Aug 1, 2026	Aug 31, 2026	30 days past due	1–30 days
Jun 1, 2026	Aug 31, 2026	91 days past due	90+ days

Frequently asked questions

What does days past due mean?: Days past due is the number of calendar days since an invoice’s due date. If payment was due August 1 and you check on August 31, the invoice is 30 days past due.
How do I calculate days past due?: Subtract the invoice due date from the calculation date using calendar days. If the due date has not arrived, the invoice is not yet overdue.
What are the standard invoice aging buckets?: Common AR aging buckets are Current / Not Due, 1–30 days, 31–60 days, 61–90 days, and 90+ days. This calculator uses those ranges.
Is 30 days overdue in the 1–30 or 31–60 bucket?: 30 days overdue is in the 1–30 bucket. 31 days overdue begins the 31–60 bucket.
Does this calculator use business days?: No. Days past due and aging buckets use calendar days, including weekends and holidays. Use the Business Days Calculator when you need working-day math.
Why do businesses track overdue invoices?: Aging overdue invoices helps prioritize collections, spot customers who pay late, and see whether old receivables are growing.

Set payment terms with the Invoice Due Date Calculator. For working-day math, use the Business Days Calculator. If you charge a late fee, try the Late Payment Fee Calculator. For accruing interest, use the Late Payment Interest Calculator. To age many invoices at once, open the AR Aging Calculator. Ready to bill? Create an invoice.