Transaction fee
A transaction fee is a per-sale platform charge that sits on top of your payment-processor fee. Shopify Basic charges 2% if you don’t use Shopify Payments; BigCommerce charges 0% on every plan; WooCommerce charges 0% (because there’s no platform to charge it). This sounds like a small number, and on a $30 product it is — about 60 cents. On $100K of annual GMV, it’s $2,000.
The reason transaction fees exist is that platform vendors want to bundle payment processing — if you take Shopify Payments, the 2% disappears, and Shopify keeps the payment-processing margin instead. The honest math is at Effective rate: it adds up to roughly the same merchant cost either way, but the choice you’re really making is whether to use the platform’s preferred gateway. For US merchants that’s usually fine. For UK/EU merchants, the regional gateway flexibility usually wins.
Why it matters at your GMV
| Annual GMV | Shopify 2% tx fee (if not on Shopify Payments) | BigCommerce / WooCommerce tx fee |
|---|---|---|
| $50,000 | $1,000/yr | $0 |
| $100,000 | $2,000/yr | $0 |
| $250,000 | $5,000/yr | $0 |
| $500,000 | $10,000/yr | $0 |
These numbers assume 100% of transactions go through a non-Shopify Payments gateway. If you use Shopify Payments for 70% and PayPal for 30%, the transaction fee applies to the 30% only. At $100K GMV and 30% PayPal mix: $600/yr in transaction fees.
Transaction fee vs payment processing fee — the difference
They are not the same.
- Transaction fee: charged by the platform (Shopify, Wix Business plan). Goes to the platform. Disappears if you use the platform’s payment product.
- Payment processing fee: charged by the payment gateway (Stripe, PayPal, Square). Goes to the gateway and card networks. Never disappears.
Every platform and every gateway charges a payment processing fee. Only some platforms charge a transaction fee on top of that.
See also: Effective rate · Payment processing fee · Shopify pricing. For the cost calculator that runs your numbers: Decision Wizard.