Business health calculator
Debtor Days Calculator
Turn average receivables and credit sales into debtor days. Your entered values stay out of analytics.
Formula and assumptions
Average receivables ÷ credit sales × days in the period
- Use average receivables: the average of opening and closing balances if you have both.
- Use credit sales only. Cash sales are not owed to you.
- The period is 365 days for a year. Change it if you use a different period, and use sales or purchases for the same period.
- Days are shown to 2 decimal places (half up).
Formula version 1.0, last reviewed 1 October 2026.
Frequently asked questions
What are debtor days?
Also called days sales outstanding (DSO): the average time between making a credit sale and being paid.
Should I include cash sales?
No. Use credit sales only; cash sales are paid at once and are not owed to you.
How is this different from the due date calculator?
The Due Date Calculator works on one invoice. Debtor days is an average across all your credit sales.