AfterSell uses Shopify's tax calculation logic for post-purchase upsells. This means that all tax settings from your store will automatically be applied to post-purchase upsells, including state-specific taxes and whether or not taxes are included in the total price. You should not need to change anything.

When editing your post-purchase upsells in AfterSell, the offer preview will not show taxes. This is to avoid confusion since there is no "correct" tax value to show. The amount of tax owed depends on many factors, including the address of the customer.

Taxes are only visible to customers for upsells with the price breakdown included. Single product upsells include the price breakdown by default. Multi-product offers hide the price breakdown by default due to the smaller screen space per product.

You can enable or disable the price breakdown for products using the "Show price breakdown" setting in the offer editor.

For products which are not taxed, such as groceries in Canada, AfterSell will not show a tax line in the price breakdown.

AfterSell does not support dynamic tax-inclusive pricing. This is due to a limitation of the Shopify post-purchase API that is described here.

For stores using regular tax-inclusive pricing, AfterSell will correctly include taxes in the prices for post-purchase upsells.

Avalara AvaTax does not work with post-purchase upsells. The tax charged for post-purchase upsells will be correct for variants with the tax code P0000000. However, the tax will be incorrect for any variants with a specific tax code, such as P1234567. This is a limitation of the Shopify post-purchase API.