One larger invoice changes the weighted measure
Durations of 10, 20 and 30 days give a 20-day mean and median. Amounts USD 1,000, 1,000 and 3,000 give a 24-day amount-weighted mean. This is a fictional selected sample, not a benchmark.
Payment reconciliation
Free Invoice Payment Cycle Calculator
Review a small, explicitly selected set of fully paid invoices. Compare their elapsed calendar days without confusing payment-cycle time with overdue days, open-invoice aging or a portfolio DSO ratio.
What you can do here
Measure issue-to-full-payment calendar days for three paid invoices, comparing mean, median and amount-weighted sample averages.
Built for real invoice workflows
Use the review to identify questions about the billing workflow, then verify causes before changing follow-up.
Preparing your calculator with today’s date…
Calculation notes
How the result is calculated
Elapsed days = full-payment date − issue date, using UTC calendar dates; same-day payment is zero. Mean gives all three invoices equal weight; median is the middle sorted duration. Amount-weighted mean = sum(duration × invoice amount) ÷ total amounts. It describes this paid sample only, excludes unpaid invoices, and is not a DSO or overdue-day calculation.
Formulas and examples reviewed October 2, 2026. Illustrative figures; no tax or contractual determination.
The same issue and payment date
Three invoices paid on their issue dates have zero elapsed days. That does not imply every outstanding invoice is paid promptly; those invoices are outside this sample.
Questions about this calculation
Is this days sales outstanding?
No. A portfolio DSO measure uses receivables and sales over a defined period. This tool uses three completed invoice cycles, so it cannot represent the unpaid portfolio.
Should the first installment be the paid date?
No. Use the date full payment is confirmed for this measurement. If credits, write-offs or refunds affected closure, review and label that case separately rather than treating it as an ordinary fully cash-paid invoice.
Sources and further reading
How to use it
1
Enter three issue dates and evidence-backed full-payment dates.
2
Enter each invoice's positive amount on the same currency and amount basis.
3
Compare the sample measures and retain its inclusion criteria.
Why it helps
Distinguish time to full payment from days past due.
See how a larger invoice affects the amount-weighted mean.
Keep a small paid sample separate from unpaid work.
Next step
From free tool to live invoice workflow.
Use the result when creating your invoice in InvoiceAgent. Planner setup links carry the settings they describe into a draft. Review your dates, amounts, PDF, and reminder settings before scheduling.
Related workflows
Move from the quick answer into the rest of the invoice system.
Record the sample evidence
Record the sample evidence
Keep issue, full-payment and inclusion references.
Review the sample limits
Review the sample limits
Separate completed cycles from unpaid aging and causal claims.
Invoice templates
Invoice templates
Use the result inside invoice formats that are ready for clients and easier to automate.
Knowledge base
Knowledge base
Review the billing concepts behind the numbers before they go onto a live invoice.
Profession pages
Profession pages
See how freelancers, consultants, and agencies apply the same calculator output in different workflows.