Gateway Fees Setup

Gateway Fees allows you to charge customers additional fees depending on the payment method used to complete a purchase.

After plugin installation you can go to Downloads → Settings →  Payment Gateways.

At the bottom of the page is an area to set up a label and either a flat fee or a percentage fee for each Gateway you have enabled.

Once you have a gateway fee set up, it automatically takes effect on the front end. Below is an example of a Stripe fee of  2.9% plus 30 cents per transaction on a $100.00 purchase.

Calculation examples

Note: Gateway Fees calculations can be very confusing.  Please read this section carefully and do experiments on your own calculations.

Something important to keep in mind is that this extension is not intended to simply add a fee to the transaction, but rather take the fees charged by the gateway and pass them on to the customer.

When the price is $100 and you want to use Gateway Fees to pass a 2.9% fee to the customer, what you actually want to do is have a total price that leaves you with $100 and still pays your fee to the payment processor. So as mentioned above, you're not using this extension to apply a fee. Instead, you're using it to offset a fee that will be applied by the payment processor.
Instead of adding 2.9% to $100, we divide $100 by 0.971 (1 minus 2.9%). What this gives us is $102.98661. This may look strange, but $102.99 is now fully prepared to pay a 2.9% fee. Here's the math: $102.99 * 0.971 (meaning minus the 2.9% fee) = $100. You get $100 while the customer pays a $3.00 fee to the payment processor.
Now in the example above there's also a 30 cent per transaction fee, so the real end total will be $103.30.

More examples

Cart Total Gateway Percentage Gateway Flat Fee Customer Pays
100 2.9% 0.30 103.30
29.99 3.3% 0.30 31.32
16.00 2.9% 0.30 16.77
42.00 4.7% 0.30 44.37
15.00 3.0% 0.00 15.46
24.00 2.9% 0.00 24.72
9.99 0.0% 0.30 10.29
49.99 0.0% 0.30 50.29