How pricing works
Subtotal, discounts, charges, tax and store credit — in that order.
Every order is priced by the server, in one fixed sequence. Knowing the sequence explains every total you will ever see.
The sequence#
- Each line: quantity × unit price, minus that line's own discount.
- Subtotal: the lines added up.
- Discounts: the engine applies whatever qualifies — product discounts first, then order discounts.
- Tax, per line, on the discounted line amount, from each product's own tax settings. Nothing typed at the till changes tax; it follows the catalogue.
- Charges: order-level and per-line fees, plus any the store's fulfilment settings add automatically (a delivery zone's fee, a dine-in service charge).
- Total = subtotal + tax + shipping + charges − discounts.
- Store credit then pays the total — it is a payment, never part of the price.
Rounding happens once per line, then whole amounts are summed — so the tax printed per line always adds up to the order's tax, to the cent.
Worked example#
Two items at 25.00 with a 5.00 line discount, 10% tax on the product, a 10% order-level charge:
| Step | Amount |
|---|---|
| Line: 2 × 25.00 − 5.00 | 45.00 |
| Subtotal | 45.00 |
| Tax: 10% of 45.00 (the discounted amount) | 4.50 |
| Charge: 10% of the 50.00 gross | 5.00 |
| Total | 54.50 |
Tax-inclusive prices#
A product marked tax-inclusive already contains its tax: a 115.00 item at 15% inclusive charges 115.00 — the invoice prints the 15.00 of tax inside it, extracted rather than added. An inclusive price never makes the total grow.
Credits and negative amounts#
A refund or credit line is a negative line — the only kind allowed to be negative. If credits outweigh the goods, the total floors at zero: the customer is never charged a negative amount, and the overflow becomes a refund only when the order explicitly asks for one (the checkout's "Create refund of {amount} for negative balance" row).