DIY Cost Tools
Sales Tax Calculator
FINANCIAL CALCULATOR
Calculate sales tax and the final price after an optional discount and quantity adjustment.
Discounted subtotal$120.00
Sales tax$8.40
Final total$128.40
How it works
The calculator applies the discount to price times quantity, then calculates tax on that discounted subtotal.
Formula
Subtotal = price × quantity × (1 − discount rate). Tax = subtotal × tax rate. Total = subtotal + tax.
Worked example
One $120 item with no discount and a 7% rate has $8.40 tax and a $128.40 total.
Important limits
- Taxability and whether discounts reduce the taxable base vary by jurisdiction and product.
- Local, state, provincial, excise, and special district taxes may combine into one effective rate.
- This is a shopping estimate, not tax advice.
Frequently asked questions
Where do I find the tax rate?
Use the current rate for the delivery or transaction location and the type of item being purchased.
Does this handle tax included in the listed price?
No. It calculates tax added to a pre-tax subtotal.
Sources and review notes
Sales-tax rules and rates vary by jurisdiction. Verify the current rate and taxable base with the applicable state or local revenue authority. Last reviewed September 29, 2026.