🔙 Reverse Percentage & Pre-Discount Solver

Reverse Percentage Calculator

Find the original base price before a discount, sales tax, or VAT percentage was applied.

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Sample Presets:
UK 20% VAT ($120 final) US 8.25% Sales Tax ($108.25 final) 25% Off Sale ($75 paid) 50% Clearance ($40 paid)
Original Pre-Adjustment Amount
$100.00
Formula: $120.00 / (1 + 0.20) = $120.00 / 1.20 = $100.00 (Tax Amount: $20.00)
Multi-Tier Sensitivity Matrix (for $120.00 final price):
Percentage RateOriginal PriceAdjustment DifferenceVerification Check

The Common Reverse Percentage Mistake

A frequent algebraic error is subtracting $20\%$ directly from a $\$120$ total ($\$120 - 20\% = \$96$), which gives the wrong base!

Before Tax (Increase): Original Price = Final Amount / (1 + Rate)
Before Discount (Decrease): Original Price = Final Amount / (1 − Rate)
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