Sales Tax Calculator
Add sales tax to a price, remove it to find the original pre-tax amount, or work out the tax rate from a before-and-after price. Doubles as a VAT and GST calculator, works with any currency and quantity — worldwide.
Pick a mode — add tax to a net price, remove tax from a gross price to find the original amount, or calculate the tax rate from a before-and-after price. Set your own rate and currency so it works anywhere.
* Tax rates and rules vary widely by country, state, province, and product category, and some prices are shown tax-inclusive while others are tax-exclusive. Enter the rate that applies to your purchase, and treat the result as an estimate. This tool is for general calculation only and is not tax or accounting advice — consult a qualified professional for filing or compliance questions.
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What Is a Sales Tax Calculator?
A sales tax calculator is a free online tool that works out the tax on a purchase and the final price you pay. It does three jobs: add tax to a pre-tax (net) price to get the total, remove tax from a total (gross) price to find the original amount and the tax paid, and find the tax rate when you know the price before and after tax. Because you enter your own rate, it works for any region and never goes out of date.
The same tool works as a VAT calculator (UK and EU), a GST calculator (Australia, India, Canada, New Zealand), and a US sales tax calculator — just pick the tax name and enter your local rate. It supports any currency and a quantity field for multi-item purchases.
How to Use This Sales Tax Calculator
- Choose a mode — add tax, remove/reverse tax, or find the rate.
- Set the tax name and currency — Sales Tax, VAT, or GST, and your currency symbol.
- Enter your figures — a price and rate (for add/remove), or a before-and-after price (to find the rate).
- Read your result — net price, tax amount, total, and the effective rate, plus a per-unit breakdown if you set a quantity.
How to Calculate Sales Tax (The Formulas)
Tax amount: Tax = Net × Rate ÷ 100
Remove tax: Net = Total ÷ (1 + Rate ÷ 100)
Find rate: Rate = (After − Before) ÷ Before × 100
Add example: a $100 item with 8.25% sales tax. Tax = 100 × 0.0825 = $8.25, so the total is $108.25.
Remove example: you paid $108.25 including 8.25% tax. Net = 108.25 ÷ 1.0825 = $100.00, and the tax portion was $8.25. This "reverse" calculation is the one most basic calculators miss.
What Is Reverse Sales Tax (and Why It Matters)?
Reverse sales tax means working backwards from a total that already includes tax to find the original price. It's essential when a receipt shows only the tax-inclusive total, when you're separating tax for expense reports or bookkeeping, or when a VAT-inclusive price needs to be broken down. The key is to divide by (1 + rate), not subtract the rate — subtracting the percentage from the total gives the wrong answer.
Sales Tax vs VAT vs GST
- Sales Tax (US): added at the point of sale; rates vary by state, county, and city, and prices are usually shown before tax.
- VAT (Value Added Tax — UK/EU): applied at each stage of the supply chain; displayed prices are typically tax-inclusive for consumers.
- GST (Goods & Services Tax — Australia, India, Canada, NZ): a broad-based consumption tax, often shown inclusive in retail.
The math is identical for all three — only the name and rate differ. That's why this one calculator covers them all.
Common Uses
- Shopping: see the real total before you reach the register.
- Freelancers & small business: add the correct tax to invoices, or strip it out for records.
- Expense reports: separate the tax portion from a tax-inclusive receipt.
- Budgeting: compare out-the-door prices across regions with different rates.
Buying something on sale? Combine this with our Discount Calculator to apply a discount and then add tax for the true out-the-door price.