How to Use the Sales Tax Calculator
- Select a state average combined rate as a planning starting point.
- Enter the taxable subtotal for items that should be included in the tax base.
- Enter exempt or nontaxable amounts separately so they do not increase the estimate.
- Add shipping and choose whether shipping should be treated as taxable for the estimate.
- Subtract discounts when the discount reduces the taxable selling price.
Sales Tax Calculator Formula
| Taxable base | Taxable subtotal - discount + taxable shipping |
|---|---|
| Sales tax | Taxable base x selected tax rate |
| Total due | Taxable subtotal + exempt subtotal + shipping - discount + sales tax |
Worked Examples
| Scenario | Input | Planning Result |
|---|---|---|
| $100 taxable purchase | 8% rate, no exempt amount | $8.00 estimated tax and $108.00 total. |
| Mixed taxable and exempt order | $80 taxable, $20 exempt, 7.5% rate | Tax applies to $80 only, before shipping and discount choices. |
| Shipping treated as taxable | $100 taxable, $10 shipping, 6% rate | Taxable base becomes $110 when shipping is included. |
What Can Change the Final Tax
Local rateCounty, city, transit, district, or special rates can change the final combined rate.
Product typeGroceries, clothing, software, digital goods, services, leases, and shipping can have different tax treatment.
Exemption statusResale, nonprofit, government, manufacturing, or other exemptions may require valid documentation.
Destination addressZIP codes and city names can cross tax boundaries, so address-level verification may be needed.
Before You Rely on the Estimate
- Open the state guide and confirm the official state source link.
- Check whether the destination has county, city, district, transit, or special local rates.
- Confirm whether the product, service, shipping charge, discount, or bundle is taxable.
- Keep exemption or resale certificate details outside the calculator if the sale is exempt.
- Use the official filing portal or source document before collecting or filing.
State Rate Shortcuts
Select a state in the calculator for a quick estimate, then open that state guide for source links, filing links, and local-rate notes.
Useful Next Steps
Use the calculator for a quick estimate, then open the relevant state guide or city page to review source links, local notes, and filing reminders before relying on the number.