The formulas
- Retention = donors who gave in both years / donors last year
- Attrition = 1 - retention
- Net change = (this year donors - last year donors) / last year donors
How it works
Donor retention shows how many of last year's donors gave again. A low rate can hide a growing cost of fundraising even when total gifts hold steady.
Count a donor once per year regardless of gift number. Choose a consistent definition of a year, such as the fiscal year, and measure first-time and repeat donors separately where you can.
Illustrative figures only. Check the result against your firm's methodology before relying on it.
Common questions
What is a typical rate?
Rates differ widely by organization and donor type. Track your own trend by cohort.
Does it include monthly donors?
Yes, count each as one donor per year.
What about reactivated donors?
Donors who skipped last year but gave this year are not retained; count them with new or reactivated donors.
Formulas on this page are the standard definitions.
Runs in your browser. The figures you type are not sent to CORAA or stored. Check the result against your firm's methodology before relying on it.