Add Paypal fee on top of donation

The actual math for that is quite complex. It sounds easy at first glance, but it’s pretty complicated to do it right. Some gateways support that as it’s own feature, unfortuantely PayPal does not.

Regardless, we created this stand-alone plugin which will add it automatically to your forms. Just download this file and install it like a plugin and it will add the percentage: https://github.com/WordImpress/Give-Snippet-Library/blob/master/form-customizations/basic-fees.php

Keep in mind that this is provided as a tool for developers. We do not provide Support for it at all at this time.

Is the calculation really complicated? Couldn’t you have a setting where the organization adds their fee structure (% + per transaction fee). Then implement a feature in the form to set it on or off and then do the simple math… (donation * % fee) + transaction fee; if the user says “i’ll pay the fee” you add it to the total.

You can take a look at how Stripe answers this question to judge the complexity:
https://support.stripe.com/questions/can-i-charge-my-stripe-fees-to-my-customers

Thanks!