Interesting question. I had a quick look at the testing done on this topic.

On the positive side, in all cases, over half of donors decide to cover the fee. In some cases, it goes as high as 65%. Not a negligible percentage at all. Here’s another test from iRaiser showing consistent results (see point 3).

That said, there seems to be some backlash

• Next After: 60% of donors covered the fees but there was a 38.5% drop in conversion rate. Even though average gift was up by 3%, overall revenue was 20.5% lower.
• Fundraise Up: they looked at impact on future donations and found that those who donate $80 or less and cover transaction costs on their first donation are 14% less likely to donate again when compared to similar donors who do not opt to cover the transaction costs. Still they recommend adding this option based on other metrics.

Unfortunately, I didn’t find any tests that also collected qualitative data to understand how people felt about the presence of this option. So I can’t be sure whether in all these studies people actually liked it, or were turned off by it but still covered fee / made a gift, or if they were completely turned off and didn’t make a gift.

My take on all this?

Just like with everything else, I suspect the answer differs from donor to donor. Some might appreciate the suggestion, regardless of whether they take it or not, while others might be turned off by it with potential negative impact on giving.

Since a significant percentage of donors decide to cover the fee, it seems like a missed opportunity not to include this option. So the question becomes: how best can we frame it to reduce potential irritation and avoid any backlash? Here are some suggestions:

• Make the extra fee reasonable
• Clearly show what the extra charge would be
• Respect the donor’s autonomy. Don’t try to trick them. People should have to opt-in, if they wish to cover the fee.
• Be transparent and add rationale. Explain how this will help you save on admin costs while at the same time it will increase the impact of their gift.
• Emphasize it’s optional and make them feel good about deciding not to cover it

Still, this practice should be tested with your own audience and results should be broken-down between meaningful segments to unearth any differences. And don’t forget to evaluate and weigh the longer-term impact of this tactic against the short-term.