Compare Stripe, PayPal, Square or a custom processor using real ecommerce profit, margin, break-even CPA and ROAS.
Editable planning assumptions. Verify current fees against your account, product and platform terms.
US online starting rates shown as editable planning presets. Your negotiated, international, wallet or alternative-payment rates can differ.
| Processor | Rate | Fee / Order | Profit / Order | Monthly Fees |
|---|---|---|---|---|
| Stripe | 2.9% + $0.30 | — | — | — |
| PayPal | 3.49% + $0.49 | — | — | — |
| Square Online | 3.3% + $0.30 | — | — | — |
| Your Custom Rate | — | — | — | — |
The calculator above compares Stripe, PayPal Checkout, Square Free online payments and a custom rate without treating processing fees in isolation. Enter selling price, product cost, fulfillment, advertising, returns, monthly software cost and other order expenses. The results card shows net profit, margin, ROI, break-even CPA, break-even ROAS and processing fee per order. A side-by-side table then applies the preset processor rates to the same order so you can see the dollar difference per sale and across monthly volume.
Processor pricing can depend on payment method, account country, international card status, currency conversion, plan and negotiated terms. Always replace the preset with the fee structure shown in the account you would actually use.
Fixed fees matter proportionally more on smaller orders. A $0.30 fixed charge is 3% of a $10 sale before the percentage fee, but only 0.3% of a $100 sale. That is why average order value should be held constant when comparing processors.
Use a $49.99 order with $18 COGS, $5.50 fulfillment, $8 advertising and $1 other cost, with no extra return or monthly charge for this simplified comparison. Stripe's U.S. domestic-card reference of 2.9% + $0.30 produces a fee of about $1.75 and modeled profit of $15.74. PayPal Checkout at 3.49% + a $0.49 USD fixed fee produces about $2.23 in processing cost and $15.26 profit. Square Free online at 3.3% + $0.30 produces about $1.95 in processing cost and $15.54 profit.
| Processor / route | U.S. reference rate | Fee on $49.99 |
|---|---|---|
| Stripe domestic online card | 2.9% + $0.30 | About $1.75 |
| PayPal Checkout | 3.49% + $0.49 USD fixed fee | About $2.23 |
| Square Free online | 3.3% + $0.30 | About $1.95 |
| Custom processor | Editable | Calculated from your inputs |
The difference between the Stripe and PayPal Checkout examples is about $0.48 per order. At 300 identical orders, that is roughly $145 before considering any feature, conversion, dispute, international-card or subscription differences. The lowest headline rate is therefore not automatically the best overall processor.
A small processing-rate difference may matter very little on a low order count but become material at scale. Profit modeling shows the fee alongside product, fulfillment, advertising and overhead.
No. The presets are U.S. online reference rates for specific payment routes. International cards, wallets, plans, currency conversion, disputes and negotiated pricing can differ.
Break-even CPA is the maximum ad cost per order. Break-even ROAS expresses the same threshold as revenue divided by that maximum ad cost.
Yes when they are required for the setup you are evaluating. Divide them across expected monthly orders so the comparison includes recurring cost as well as transaction fees.
Rates checked September 25, 2026 against Stripe, PayPal and Square. Match them to your own account before deciding.