Reverse Sales Tax Calculator

$400.00 + 21% tax= $330.58 Original Price (before tax)

See exactly how we calculated the pre-tax price from your tax-inclusive amount. Our step-by-step breakdown shows the precise mathematics behind removing sales tax from a total price.

Quick Reference

Final Price (with tax)$400.00

Tax Rate (%)21%

Tax Amount$69.42

Original Price (before tax)$330.58

Calculation Steps

Final price with tax: $400.00

Convert tax rate to decimal: 21% ÷ 100 = 0.210

Calculate divisor (1 + tax rate): 1 + 0.210 = 1.210

Divide final price by divisor: $400.00 ÷ 1.210 = $330.58

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How It Works

To find the original price before tax, divide the tax-inclusive amount by (1 + tax rate as decimal). This calculator handles the math for you, showing each step of the process.

The Formula

Original Price = Final Price ÷ (1 + Tax Rate%/100)

Example Calculation

For a final price of $400.00 with 21% tax rate, divide $400.00 by (1 + 21/100) to get the original price of $330.58. The tax amount is $69.42.