Everyday Math
Sales Tax Calculator — Calculations & Slabs for FY 2026-27
Enter the item price and your local sales tax rate to compute the tax amount and final price including tax -- or back-calculate the pre-tax price from a tax-inclusive total.
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Enter your local tax rate — GST, VAT, or Sales Tax
📊 Sales Tax Mathematics
Sales tax is a consumption tax charged on the sale of goods and services. Calculating it depends on whether you are adding tax to a net price or removing tax from an all-inclusive total price.
Addition (Exclusive Tax) Formulas
When prices are tax-exclusive, tax is added at checkout:
- Tax Amount: Multiply the pre-tax price by the tax rate:
Tax Amount = Pre-Tax Price × (Tax Rate % / 100) - Total Price: Add the tax amount to the pre-tax subtotal:
Total Price = Pre-Tax Price + Tax Amount
Reverse (Inclusive Tax) Formulas
To find the subtotal from an all-inclusive total price:
- Pre-Tax Subtotal: Divide the total price by 1 plus the tax rate as a decimal:
Pre-Tax Subtotal = Total Price / (1 + Tax Rate % / 100) - Tax Component: Subtract the subtotal from the total price:
Tax Amount = Total Price - Pre-Tax Subtotal