🧾 Sales Tax Calculator
Calculate sales tax and final price. Enter amount and tax rate for instant results.
About the Sales Tax Calculator
This sales tax calculator runs entirely in your browser. Enter the pre-tax amount and the tax rate, then click Calculate to see the tax amount and final price with tax included. Use Reverse Calculate to find the pre-tax amount from a total that already includes tax. Nothing is uploaded — all math happens on your device.
How sales tax is calculated
Forward calculation: tax = amount × (rate / 100), total = amount + tax.
Reverse calculation: if you have a total that includes tax, original = total ÷ (1 + rate / 100), tax = total − original.
tax = amount × rate / 100 | total = amount + tax
reverse: original = total / (1 + rate / 100)
How to use the calculator
- Enter the Amount before tax.
- Enter the Tax rate as a percentage (e.g., 8 for 8%).
- Click Calculate for the forward calculation, or Reverse Calculate to find the original amount from a tax-inclusive total.
- Results update live as you type.
Frequently asked questions
What's the difference between forward and reverse? Forward adds tax to a base amount. Reverse removes tax from a total that already includes it.
Can the tax rate be 0? Yes. A 0% rate means no tax — the total equals the original amount.
Can I use a negative tax rate? Technically yes, but it's unusual. Negative rates would act as a discount.
Does this tool save my data? No. All calculations happen locally in your browser.