Fixed amounts and calculated amounts
Choose the amount a payment form collects and check it before connecting a payment method.
Choose the amount rule before configuring the payment provider. A workshop ticket with one price can use a fixed amount. A booking with different packages needs an amount based on the customer's choices. A donation can use an amount entered by the respondent.
Choose an amount source
| Need | Amount source |
|---|---|
| Every respondent pays the same fee | A fixed numeric amount |
| The fee changes with a selected option | A calculated form field |
| Products have prices and quantities | The final order amount field |
| The respondent chooses a contribution | A numeric donation amount field |
Use one currency for the form and its payment configuration. A currency symbol on a label is not a currency conversion rule.
Configure the form
- Add the information and choices the respondent must supply.
- Add or select the field that represents the amount due. For a calculated field, open its settings and use Answer → Calculate.
- Make a total intended only for display read only, so customers cannot overwrite it.
- In payment configuration, choose the final amount field. In an older Stripe configuration this control is labeled Pick amount from.
- Save and preview the form.
Check representative answers
Try the lowest-priced option, the highest-priced option, and more than one quantity. Include any discount, tax, or delivery fee your business has configured. A simple example is two tickets at 15 each: the amount should be 30 before any additional rule applies.
For donations, decide whether zero or a minimum contribution is acceptable and configure the answer validation accordingly. Avoid allowing arbitrary text in the amount field.
If the preview total is correct but checkout shows a different amount, recheck the selected payment field. See incorrect totals and the calculation reference.