Sales Tax Calculator
Use this calculator when a price needs tax added at checkout, or when a receipt already includes tax and you need the net amount. It works with US sales tax, VAT, GST and any custom rate, as long as you enter the combined rate that applies to the transaction.
How to calculate sales tax, VAT or GST
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1
Pick the calculation
"Add tax" starts from a tax-exclusive price. "Extract tax" starts from a tax-included total.
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2
Enter the amount
Use the net amount when adding tax, or the gross amount actually paid when extracting tax.
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3
Enter the rate
Use the total rate for the item and place, such as 8.875% sales tax, 20% VAT or 10% GST.
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4
Check the breakdown
The calculator returns the net amount, tax amount and gross total, rounded to 2 decimals.
Adding tax vs extracting included tax
Adding tax and extracting included tax are not mirror images. If you subtract 8% from a tax-included total, you do not get the same net price as dividing by 1.08.
Formulas
| Operation | Formula | Example |
|---|---|---|
| Add tax to a net price | Gross = Net × (1 + rate) | $100.00 × 1.08875 = $108.88 |
| Calculate the tax amount | Tax = Net × rate | $100.00 × 0.08875 = $8.88 |
| Extract tax from a gross price | Net = Gross ÷ (1 + rate) | $108.88 ÷ 1.08875 = $100.00 |
| Extract the tax portion | Tax = Gross - Net | $108.88 - $100.00 = $8.88 |
Local tax habits to keep in mind
- US sales tax is usually added at checkout. State, county, city and district rates can stack, so enter the combined local rate. Some states have no statewide sales tax, while local taxes can still apply.
- VAT and GST markets normally show consumer prices tax-included. Use “Extract tax” to split a gross receipt into net price and tax, or “Add tax” for business quotes that start from a net amount.
- Reduced and zero rates may apply to food, books, medicines, exports or other categories. This calculator only does the arithmetic; it does not decide which legal rate applies.
Gotchas
- Shipping and fees: some jurisdictions tax delivery or service fees, others do not.
- Destination vs origin: US sales tax may depend on the buyer location, the seller location or special marketplace rules.
- Compound or tax-included systems: not every tax is a simple add-on. If a tax is included in its own base, confirm the correct local formula before filing.
- Rounding: many point-of-sale systems round each line item, then sum the rounded values. One calculation on the final total can differ by a cent or two.
Frequently Asked Questions
If every component applies to the same taxable base, add the percentages and enter the combined rate. For example, 4% state + 4.5% city + 0.375% district = 8.875%.
Yes. Enter the VAT or GST rate and choose the direction that matches your price. Use “Extract tax” for a consumer price that already includes tax.
A register may round tax on each line item, then add those rounded values. A calculator that works from the final total rounds only once, so tiny differences are normal.
They are not. The math happens in your browser and the values you enter are never uploaded or logged.
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