Invoice Aging Calculator
Add up your unpaid invoices by how long they are past due to see total receivables and how much of it is overdue.
Open invoice balances ($)
Enter the unpaid amount in each age group, counted from each invoice's due date. Leave a field blank for $0.
Total open receivables
$9,850.00
- Past due (1 day or more)
- $5,650.00 (57.4%)
- More than 90 days past due
- $950.00 (9.6%)
Share of total by age
- Not yet due
- $4,200.00 (42.6%)
- 1–30 days
- $2,300.00 (23.4%)
- 31–60 days
- $1,600.00 (16.2%)
- 61–90 days
- $800.00 (8.1%)
- Over 90 days
- $950.00 (9.6%)
Share = bucket ÷ total open receivables × 100, rounded to one decimal place, so the shares may not add up to exactly 100%.
How the calculation works
An aging schedule groups unpaid invoices by how many days have passed since each one was due. This calculator adds the five groups together and shows each one as a share of the total:
- Total open receivables = the sum of all five buckets.
- Past due = every bucket except “Not yet due”.
- Share of a bucket = bucket ÷ total × 100, rounded to one decimal place.
Amounts are in dollars and shown to the cent. If you work in another currency, enter every bucket in that currency; the percentages are the same.
Worked example
The sample figures in the calculator are $4,200 not yet due, $2,300 at 1–30 days, $1,600 at 31–60 days, $800 at 61–90 days and $950 over 90 days. The total is $9,850. Past due is $5,650, which is 57.4% of the total ($5,650 ÷ $9,850 = 0.5736). The over-90 bucket is $950, or 9.6%. The five rounded shares (42.6%, 23.4%, 16.2%, 8.1% and 9.6%) add up to 99.9% because of rounding.
Why the age matters
The OpenStax Principles of Accounting textbook explains that the longer a receivable stays unpaid, the lower the probability it will be collected. That is why accountants who estimate bad debts with the aging method assign a higher uncollectible percentage to older buckets. In practice, it means the oldest balances deserve the earliest follow-up.
For the follow-up itself, read how to follow up on unpaid invoices and our guide to accounts receivable management. To work out a late fee on one overdue invoice, use the late fee calculator.
Frequently Asked Questions
- Where do the bucket amounts come from?
- From your list of unpaid invoices. For each invoice, count the days since its due date and add its unpaid balance to the matching bucket. Invoices that aren't due yet go in "Not yet due". Your accounting software's accounts receivable aging report gives the same totals if it uses the same buckets.
- Why are older balances shown separately?
- Because they are less likely to be collected. The OpenStax Principles of Accounting textbook puts it this way: the longer a receivable stays unpaid, the lower the probability that it will be collected, and an account 90 days overdue is more likely to go unpaid than one 30 days past due.
- What if a customer has a credit balance?
- This calculator only accepts amounts of 0 or more, so leave credits out and net them off in your own records. Mixing credits into a bucket would understate how much is overdue in it.
- Does this calculator save or send my numbers?
- No. The calculation runs in your browser and nothing you type is stored. Your accounting records remain the source of truth; this is a quick way to see the mix.
Stay ahead of overdue invoices
Billed's invoice reports show paid, partially paid and overdue invoices, and you can send payment reminders to customers who owe you.
No credit card required.