Tax and custom calculations

Use calculated fields when the amount depends on selected products or answers. Keep each component visible enough for you to check how the final amount is produced.

Open the calculation

In the editor, open the target question's gear and choose Answer → Calculate. Use @ to insert another answer and the function picker for supported functions.

Set calculated amount fields to a suitable read-only appearance so customers see the value produced by their choices. A hidden field can carry a value for reporting, but customers still need a clear final amount.

Choose the calculation base

Decide whether a percentage applies to the product subtotal, a discounted subtotal, or another component. Use the field representing that base rather than repeatedly rebuilding the whole total.

For a fictional example, a business applying 8% to a $20 taxable base would calculate $1.60. The example illustrates arithmetic; use the rate and treatment that apply to your own business.

Avoid double counting

If a product has a Tax (in %) setting, inspect how that configuration affects the total before adding another tax field. Similarly, do not add delivery twice through both a product and a delivery-fee calculation.

Write down the expected subtotal, discount, fee, tax, and amount for a sample order. Compare each component with the form before sharing.

Conditional calculations

Use IFS when different conditions produce different amounts. Put the most specific condition first, because the first matching condition supplies the result. Include an appropriate fallback for orders that match none of the conditions.

The discount guide provides a tiered example. Use the calculation reference for function syntax.

Maintain the calculation

After renaming or replacing a referenced field, reopen the calculation and preview it again. Check both sides of every threshold and an empty or unselected answer. When the total is wrong, inspect order troubleshooting before taking customer orders.