Why did it start adding tax to all my estimates? I have the box checked nontaxable.

Thanks for joining the Community, laserlinepaintin.

Since taxes are being added to your estimates, I'd initially recommend checking the customer's profile to see if they have an address listed. If there isn't one, or there's an incorrect one, you'll want to update it with their appropriate information. This will assure taxes are applied properly based off their location.

Next, I'd also recommend making sure they're set up as non-taxable in their profile.

Here's how:

1. In your left navigation bar, go to Sales, then Customers.
2. Find the customer, then click their display name.
3. Click Edit and access your Tax info tab.
4. Confirm that the This customer is taxable option is unticked and enter any appropriate Exemption details if necessary.
5. If any changes were made, select Save.

You'll also want to make sure your products and services you're selling to these customers are set up as non-taxable:

1. Go to Sales, then Products and services.
2. One by one, locate each product/service being sold to the customer and use their Edit options.
3. Double-check their Sales tax area by clicking Edit sales tax, then confirm it's set to Nontaxable.
4. If changes were made, hit Done, then Save and close.
   

Additionally, when creating sales receipts, I'd recommend making sure their tax option's turned off.

I've also included a detailed resource about working with sales taxes which may come in handy moving forward: Learn how QuickBooks calculates sales tax

Please don't hesitate to send a reply if there's any questions. Have a lovely day!