Tax Toggle changes the price shown to a visitor using WooCommerce's tax calculations. If the numbers stay the same, work through these checks with a product that should have a non-zero tax amount.
Check that tax calculations are enabled
In WooCommerce → Settings → General, make sure Enable tax rates and calculations is selected. Save changes if you update it.
Check the product and its tax class
Open the product in WordPress. In Product data → General, set Tax status to Taxable if that product should be taxed. Check its tax class if you use more than one class.
A zero-rated or non-taxable product can legitimately show the same amount in both toggle states.
Check the rate for your test location
Go to WooCommerce → Settings → Tax and inspect the rates for the product's tax class. The applicable rate depends on the address WooCommerce uses and the visitor location.
Check Calculate tax based on and Default customer location against your intended store configuration. Avoid adding a worldwide rate just to make the display change; it could apply tax to the wrong customers.
WooCommerce explains these settings in its tax configuration guide.
Test an uncached visitor session
Open the product in a private browser window and switch the toggle. If you use a page cache or CDN, clear the affected page cache and test again.
If one theme or another plugin replaces WooCommerce price markup, test with a standard theme and other plugins disabled on a staging site. Do not interrupt checkout on your live store for this test.
Still stuck?
Send us the product URL, the two prices you expect, the tax location used for testing, and your Tax Toggle and WooCommerce versions through support. Do not send a license key or login credentials.