Multiple merchants are experiencing a critical issue where Shopify recalculates and updates sales tax amounts after customers complete checkout. The original charge gets voided and a new, higher charge is authorized, causing customer complaints about apparent overcharging.
POS in-person transactions: Taxes initially calculated correctly but then removed from some items before payment
One merchant reports their system shows tax being refunded to customers at order completion
Issue has cost merchants hundreds of dollars and is causing lost orders
Suggested Troubleshooting:
Audit third-party tax apps that might trigger recalculations
Consider manual tax rate overrides to prevent automatic updates
Check if address validation is causing post-checkout tax adjustments
Escalate to higher-level Shopify technical support
Current Status: Unresolved. Merchants express frustration that Shopify support provides inadequate responses and hasn’t addressed what they view as a fundamental platform flaw. Multiple users note competing platforms handle tax calculation accurately at checkout.
Summarized with AI on October 28.
AI used: claude-sonnet-4-5-20250929.
Has anypne had experience where an online order has had the tax amount change after customer checked out? We have had a few times where the customer pays, and then shopify ‘updates’ the tax information after the fact and then charges then again. The initial charge is voided and a second charge is authorized after the fact. This has happened to us several times and the customers are always angry- and rightly so. they think we are over charging them after the fact. When i ask shopify about it I get the most ridiculous uneducated answers from their support- one even told me that maybe my state (California) had changed their tax rates mid transaction…
This issue with Shopify updating the tax amount after a customer has checked out is frustrating and understandably causing customer dissatisfaction. Here’s a concise breakdown of possible causes and solutions:
Possible Causes:
Third-Party Apps: Sometimes, tax apps or third-party integrations can update the tax calculation after the transaction.
Address Validation: Shopify may update tax rates if it receives updated address information post-checkout.
Shopify Tax Calculation: Shopify’s tax engine could be recalculating taxes if there’s a delay or error in the initial calculation, possibly due to server-side issues.
Solutions:
Audit Third-Party Apps: Check if any tax-related apps are integrated with your store and causing recalculations. Disable them temporarily to test.
Manual Tax Override: If the issue persists, consider setting up manual tax rates for your state to avoid automatic updates.
Clear Communication: Notify customers at checkout that taxes are estimated and may adjust slightly based on address validation, but that double-charging is not your intention.
Shopify Support Escalation: Request to escalate the issue to a higher level of Shopify support or a technical specialist who can investigate the backend processes and resolve the problem.
If it resolves your issue, please mark my answer as a solution or if you still need assistance, let me know. Thank you.
We have also had this consistent problem on our POS in person. We thought maybe if we “categorized” each item it would charge sales tax correctly. It does not. There are no apps messing with this. It charges taxes initially and then when we go to have customers pay it removes taxes on some, but not all items. It has cost us hundreds of dollars.
In addition, on my other store, it’s charging customers sales tax and at the bottom of the order says it’s sending the tax money back to them. This is horrible. To the point I may change away from Shopify. It will literally cost me hundreds of dollars.
And make our taxes excruciating to do. If you’re for small businesses, fix these HUGE glitches that hurt us.
Yes, this is happening to us and it is RIDICULOUS that noone at Shopify is doing anything about it apparently. They are ignoring a HUGE issue, customers should not be faced with a higher bill AFTER the fact, no warning provided. Shopify should have the technological ability to calculate taxes accurately at checkout based on the information provided by the customer, and if the customer then changes the address it should be able to re calculate taxes then.
Walmart, Amazon, Ebay and all other major online stores and Ecommerce platforms have figured this out, Shopify is still in the stone age.