How do you handle taxes for Buy One, Get One (BOGO) deals in Shopify without creating tax mismatches?

Buy One, Get One promotions can get confusing when it comes to sales tax, especially depending on the state and how the discount is applied at the line-item level.

In some cases, it looks like tax is calculated on the pre-discount price instead of what the customer actually paid. How are others handling BOGO deals to make sure tax is being calculated correctly and reporting stays accurate?

hii @webgility_hq

In Shopify tax is calculated on the post-discount line price. If tax looks like it’s based on the pre-discount amount, it’s typically because the BOGO is implemented as

A cartautomatic discount applied at checkout or
A $0 item added as the free product

For accurate tax reporting especially in US states

Apply BOGO as a line-item discount split across itemsnot a cart-level discount
Avoid making items truly $0 if the state requires value allocation
Let Shopify’s tax engine handle the allocation rather than custom scripts

This keeps tax calculation and reporting consistent with state rules.

Thanks