Days Past Due Calculator
Count how many calendar days an invoice is past due and which AR aging bucket it falls into.
How is days past due calculator worked out?
Days past due is the number of calendar days between an invoice's due date and today. Anything not yet due is current; past-due invoices are grouped into 1–30, 31–60, 61–90 and 90+ day buckets for aging analysis.
Days Past Due Calculator
Days until due
0 days
- Aging bucket
- Current
Show the working
| Due date | 31 August 2026 |
| As-of date | 31 August 2026 |
| Days remaining | 0 days |
| Aging bucket | Current |
This invoice is not yet due, so it sits in the current bucket.
Days past due is the trigger for every collection decision you make: which invoice to chase, how firmly, and when to escalate. The bucket matters as much as the number, because the probability of collecting falls sharply the further right an invoice moves.
The formula
Days past due = as-of date − due date (calendar days)
A result of zero or less means the invoice is current.
Buckets: 1–30, 31–60, 61–90, 90+ days past due.Aging is measured from the due date, not the invoice date. Aging from the invoice date makes every invoice look worse than it is and makes your terms invisible in the analysis.
What the buckets are for
Grouping receivables by how far past due they are turns a list of invoices into a picture of collection risk. Invoices in the 1–30 bucket are usually administrative — lost in an inbox, waiting for an approval, missed a payment run — and a reminder generally clears them. By 61–90 days the reason is more often deliberate or contested, and beyond 90 days the realistic likelihood of collecting in full drops considerably. That falling curve is why the buckets exist: they tell you where the effort is worth spending.
Aging from the due date, not the invoice date
An invoice issued on Net 60 terms and paid on day 55 was never late, but aged from its invoice date it would show as nearly two months old. Measuring from the due date keeps aging comparable across customers on different terms and stops your own generous terms from looking like a collections problem. If your reports show different numbers from your customers', this is usually why.
Frequently asked questions
How do you calculate days past due?
Subtract the invoice due date from today's date and count the calendar days. If the result is zero or negative the invoice is not yet due; if it is positive, that is how many days past due it is.
What are the standard AR aging buckets?
Current for invoices not yet due, then 1–30, 31–60, 61–90 and 90+ days past due. Some businesses use 120+ as a further bucket for debts approaching write-off.
Is days past due measured from the invoice date or the due date?
From the due date. Measuring from the invoice date mixes your payment terms into the aging figure and makes invoices on longer terms look overdue when they are not.
Put the number on an invoice
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