How to Charge the Right Sales Tax at Checkout

Getting checkout right protects your margin and your customers. Here is how.

September 3, 2026 · 3 min read

The rate depends on the address

For most remote sales, the correct rate is the combined rate at the customer's shipping address. That means checkout needs to determine the rate per order, not apply a fixed number.

Use an address level lookup

An address based rate lookup returns the exact combined rate for where the order ships. Building this into checkout is the reliable way to charge correctly across thousands of jurisdictions.

Show the breakdown

Displaying how the tax is composed, or at least being able to explain it, builds customer confidence and helps you stand behind the number if it is ever questioned.

Keep clean records

Whatever you charge, record it clearly per order. Good records make filing straightforward and protect you if you ever need to reconcile what you collected with what you owe.

Key takeaways

The correct rate depends on the ship to address
Use an address level lookup, not a flat rate
Be able to show how the tax is composed
Keep clean per order records for filing

Written by

Julien Jimenez

Julien Jimenez is an independent software builder based in Paris. He designs, ships, and operates focused SaaS products for small businesses and independent professionals. Read the full author page.