Wrong tax at checkout: WooCommerce tax and VAT errors
Tax errors rarely stop a checkout. They do something arguably worse: the order goes through at the wrong total. You either undercharge and pay the difference, or overcharge and lose the sale or the customer’s trust.
Common mistakes
Rates missing for a country or region you started shipping to, products in the wrong tax class, tax based on billing address when it should be shipping address, prices entered inclusive of tax on one product and exclusive on another. The WooCommerce tax setup guide covers the options.
Tax plugins and automated tax services add another dependency: when their API fails, tax can silently become zero.
EU VAT specifics
Stores selling to consumers across the EU charge VAT at the customer’s country rate in many cases, and B2B sales with a valid VAT number may be reverse-charged. A VAT number validation service that is down can block business customers at checkout.
These are the same kind of per-market problems as in multi-store Magento: fine in one country, wrong in another.
Checking the numbers
Test orders to each tax region you sell to and compare the tax line with what it should be. Repeat after changes to tax settings, tax plugins or product imports.
A checkout check that asserts the order summary — subtotal, shipping, tax, grand total, arithmetic included — catches tax that disappears. MageSentinel reports that as a TAX failure, separate from a checkout that will not load.
Check your own store now with the free WooCommerce checkout checker: it walks the checkout in a real browser and shows the step where it stops.
When totals or shipping do not refresh, see WooCommerce update_checkout not working.
Common questions
Why is WooCommerce calculating the wrong tax?
Tax based on the wrong address (shop base vs billing vs shipping), missing rates for a country, wrong tax class on products or shipping, or rounding settings.
How do I charge EU VAT by customer country?
Add standard and reduced rates per EU country and calculate tax on the customer address; under the OSS scheme you charge the customer country’s VAT.
How do I check tax is right?
Place test orders to addresses in each country you sell to, with each tax class, and compare totals with the expected figures.