A payment gateway’s percentage fee and fixed charge can be calculated in two directions. You may already know what the customer will pay, or you may need a specified amount to arrive after fees. The Payment Gateway Calculator has separate modes because adding a percentage to the desired net amount is not the same as solving for gross.
Calculate a known customer charge first
Choose gross mode and enter PKR 1,000. Use an illustrative fee of 3%, a fixed charge of PKR 20 and 10% tax on the fee. The percentage component is PKR 30. Adding the fixed charge produces PKR 50 in gateway fees.
Tax on that fee is PKR 5. Total deductions are PKR 55, leaving a net receipt of PKR 945. The tax field applies to the gateway fee, not the complete customer payment.
Work backwards when the net amount is the target
Switch to net mode and request PKR 945 with the same three fee inputs. The result returns a gross payment of PKR 1,000. This provides a useful check that both directions are using the same fee contract.
The inverse calculation accounts for tax on both the percentage fee and the fixed fee. It does not simply multiply PKR 945 by 1.03. That shortcut overlooks the fixed deduction and charges the percentage against the wrong final amount.
A small payment can leave very little cash
Fixed fees do not shrink with the sale. For a low value transaction they can absorb most of the receipt, and gross mode can show a negative net result if deductions exceed the payment. That is a cost warning, not a guaranteed refusal by the provider.
In net mode, an effective percentage deduction reaching 100% makes the requested positive net amount impossible under the model. The tool rejects that input combination rather than presenting a misleading price.
Check the provider’s rounding and refund policy
The displayed money is rounded, while the calculation uses greater internal precision. A processor may round each line differently or retain a fixed fee after refund. Match one real settlement before relying on the estimate for a payment campaign.
These example charges are not a provider recommendation or live rate feed. Use Target Selling Price Calculator if the required selling price must also cover product, delivery and advertising costs; gateway deductions alone do not establish profit.