Asking donors for a mailing address in Checkout

Making the mailing address field mandatory in Checkout reduced donation conversion by more than 3%.

What we tested

We tested what happens when donors are required to fill in a mailing address during Checkout, compared to the current default, where it's optional. The test ran across campaigns that already had the mailing address field set to optional, measuring how enforcing it as mandatory affects donors' likelihood to complete their gift.

Organizations in Canada and Germany were excluded, as mailing address entry is already mandatory in those markets. Payment methods that require a mailing address by default — such as UK BACS and certain SEPA configurations — were also excluded.

Hypothesis

If we make the mailing address field mandatory in Checkout, donation conversion will decrease by at least 3% because the added friction of an additional required field will cause some donors to abandon before completing their gift.

Test setup

Duration	14 days
Timing	January 2024
Audience	~34,000 visitors who reached the privacy screen in Checkout
Group split	• 50% control (mailing address optional) • 50% test (mailing address required)
Key metrics	• Donation conversion rate (visitors who reached the privacy screen and completed a donation) • Average Revenue Per User (ARPU) • Average Revenue Per Paying User (ARPPU) • Fee coverage rate

Key results

Making the mailing address mandatory had a clear negative impact on conversion and revenue.

3.4% decrease in donation conversion
4.8% decrease in ARPU
ARPPU and the fee coverage rate showed no statistically significant difference

The conversion drop was consistent across operating systems and device types, confirming these results are reliable.

Segment insights

By device type

The negative effect was stronger on mobile than on desktop. All differences below are statistically significant (p < 0.05).

Mobile: -4.3% conversion, -6% ARPU
Desktop: -1.9% conversion, -3.7% ARPU

By OS

All major operating systems saw significant drops:

Android: -4.4% conversion, -8.1% ARPU
iOS: -4.3% conversion, -5.2% ARPU
Windows: -1.6% conversion
Mac OS: -2.7% conversion

By region

Conversion declines were observed across key markets:

U.S.: -2.5%
EU: -7.7%
Australia: -5.8%
Great Britain: -3.6%

Recurring vs. one-time donations

One-time conversion: -3.5% overall
Recurring conversion: No statistically significant difference observed

All key metrics passed the threshold for statistical significance (p-value < 0.05), confirming that these improvements are reliable.

3.4%

decrease in donation conversion

4.8%

decrease in ARPU

4.3%

decrease in donation conversion on mobile

Conclusion

The data is clear: requiring a mailing address in Checkout creates friction that costs donations. The negative effect is most pronounced on mobile and in markets outside the US. Recurring giving was not significantly impacted, but one-time donors — the majority of all donors — were meaningfully affected.

This test was conducted to generate knowledge, not to roll out a change. The mailing address field will remain optional by default. These results give us concrete data to share with organizations that are considering enabling the mandatory mailing address setting, so they can make an informed decision knowing the trade-offs involved.

What this means for you

Every field you add to Checkout has a cost — especially on mobile, where donors are most sensitive to friction. This test shows that even a single required field can reduce donation conversion by more than 3% overall, and by over 4% on mobile.

Fundraise Up tests these trade-offs so you don't have to. If your organization needs mailing address data, you can still collect it, but now you have the data to understand what it may cost in conversion.

→ Explore how Checkout optimizations can improve your fundraising results