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# Donor Lifespan

## What is Donor Lifespan?

Donor Lifespan is a calculation of how long (in time) you can expect to receive donations from a donor before they churn. This metric is used in the equation for lifetime value. In the Fundraising Report Card, we calculate lifespan in terms of years. A long donor lifespan is a good thing! It means on average, your constituents are engaging with your organization for a long period of time before they lapse.

## How is it calculated?

The Donor Lifespan calculation is simple, it just takes some help from a computer to run the equation.
We calculate the number of years each individual donor makes a gift to your organization, and find the average of that sum. The equation looks something like this:
**Lifespan** = cumulative years of giving รท total # of donors