AnyTool
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How do I calculate a discount and the sale price?

Pick a mode in AnyTool Discount Calculator and type your numbers. For a percentage discount it multiplies the original price by (1 − percent ÷ 100) to get the sale price and shows the savings; for a flat amount off it simply subtracts the coupon value. It can also reverse a sale price back to the original, find the discount % from the original and sale prices, and stack a chain of discounts — applying each cut to the already-reduced price so the combined discount multiplies rather than adds (20% then 10% is 28% off, not 30%). An optional sales tax is applied after the discount, and the savings, sale price and effective % appear live in your browser.

  • Percent off: sale price = original × (1 − percent ÷ 100); savings = original − sale
  • Amount off: sale price = original − coupon (a flat ₹/$ off)
  • Reverse: original = sale price ÷ (1 − percent ÷ 100)
  • Stacked discounts multiply: 20% then 10% = 28% off, not 30%
  • 100% in your browser — no upload, no signup, works offline

What is

Discount (percent off, amount off, stacked)

A discount is a reduction from a product’s original (list) price. A percentage discount removes a share of the price (sale price = original × (1 − rate)); a flat amount-off coupon subtracts a fixed sum. Stacked (or double) discounts are applied in sequence, each one cutting the already-reduced price, so their combined effect is the product of the survival factors — (1 − r₁)(1 − r₂) — not the sum of the rates. The effective discount is the total savings expressed as a percentage of the original price.

Calculators

Related terms

Sale pricePercent offStacked discountReverse discountEffective discountSales tax

Frequently Asked Questions

Sale price = original × (1 − percent ÷ 100), and you save original × percent ÷ 100. A $100 item at 25% off costs $75 and saves $25.

To find a sale price from a percentage discount, multiply the original price by (1 − percent ÷ 100); the savings are original × percent ÷ 100. For example, $100 at 25% off gives $25 savings and a $75 sale price. AnyTool Discount Calculator computes this live, and also handles a flat amount-off coupon by subtracting the coupon directly from the price.

No. Stacked discounts multiply, not add. 20% then 10% is 1 − (0.80 × 0.90) = 28% off, so a $100 item costs $72, not $70.

Stacked or double discounts are applied one after another, and the second discount only acts on the already-reduced price, so the combined discount is the product of the survival factors, not the sum of the rates. A 20% discount followed by an extra 10% is 1 − (0.80 × 0.90) = 28% off — a $100 item lands at $72, not $70. AnyTool’s Stacked mode traces each step and shows the real effective percentage next to the naive sum so the gap is obvious.

Divide the sale price by (1 − percent ÷ 100). A $72 price that was 28% off came from $72 ÷ 0.72 = $100.

To reverse a discount, divide the sale price by (1 − percent ÷ 100) to recover the original list price. For instance, a $72 item that was 28% off started at $72 ÷ 0.72 = $100. AnyTool’s Find-original mode does this, and a separate Find-% mode works out the discount percentage when you know both the original and the sale price: percent = (original − sale) ÷ original.

Yes, it is free with no signup, and nothing is uploaded — every calculation runs in your browser and the page works offline.

AnyTool Discount Calculator is completely free with no account or limits, and all math runs on a small, unit-tested engine entirely in your browser, so the prices you type are never sent to a server. Sales tax is applied after the discount on the reduced price, which is the usual retail order, though tax rules vary by region and a checkout may round the final cent differently.

Detailed Explanation

Methodology

How the Discount Calculator Works

The calculator offers five modes built on simple price identities. Percent off computes sale price = original × (1 − percent ÷ 100) and savings = original − sale. Amount off subtracts a flat coupon value from the price. Reverse recovers the original from a discounted price as original = sale ÷ (1 − percent ÷ 100). Find-% derives the discount as percent = (original − sale) ÷ original. Stacked applies a sequence of percentage discounts in order, multiplying the survival factors. Every result is produced by a pure function in a small, unit-tested engine, with the worked formula shown and an optional sales tax applied after the discount.

  • Percent off: sale = original × (1 − percent ÷ 100)
  • Amount off: sale = original − flat coupon value
  • Reverse: original = sale ÷ (1 − percent ÷ 100)
  • Find %: percent = (original − sale) ÷ original × 100
  • All math is client-side JavaScript with no server round-trip
How It Works

Stacked Discounts Multiply, They Do Not Add

The single most common discount mistake is adding stacked percentages. Two discounts applied in sequence each act on the already-reduced price, so the combined effect is the product of the survival factors: final = original × (1 − r₁) × (1 − r₂). A 20% discount followed by an extra 10% is 1 − (0.80 × 0.90) = 28% off, so a $100 item costs $72, not the $70 implied by adding 20 + 10. The calculator’s Stacked mode traces each step and prints the true effective percentage right beside the naive sum. Because multiplication commutes, the order of percentage discounts does not change the final price, but inserting a flat amount-off coupon into the chain does depend on order.

  • Final price = original × (1 − r₁) × (1 − r₂) × …
  • 20% then 10% = 28% off, not 30% — $100 → $72
  • Effective discount = (1 − product of survival factors) × 100
  • Order of percentage discounts does not change the result
  • Tool shows the real combined % next to the naive sum
Limitations

Sales Tax, Rounding and What This Cannot Decide

When enabled, sales tax is applied after the discount on the reduced (sale) price — the usual retail order — as tax = sale × rate ÷ 100, giving a final price of sale + tax. Tax treatment, however, varies by jurisdiction, and a checkout system may round the final cent differently from a pure calculation. The tool also assumes a single list price and does not model per-item caps, minimum-spend thresholds, buy-one-get-one offers, loyalty points or currency conversion. Figures are rounded to two decimals for display while full precision is used in the math.

  • Sales tax applied after the discount: tax = sale × rate ÷ 100
  • Tax rules vary by region; checkouts may round differently
  • Does not model BOGO, spend thresholds or loyalty points
  • Effective % is savings expressed against the original price
  • An estimator for shopping and pricing — not a billing system
Privacy & Security

Privacy and Offline Use

Because all computation runs in the browser, the prices you enter are never sent to a server, there is no account or tracking, and the page works offline after first load. The calculator is built on a shared, unit-tested discount engine so its behaviour is consistent and verifiable across modes, and the full breakdown — including the stacked step trace — can be copied to the clipboard with one tap.

Discount calculation: in-browser (AnyTool) vs typical online discount calculators
CapabilityAnyToolTypical online discount calculators
ProcessingRuns in your browserOften server-side
Modes5 (% off, $ off, reverse, find %, stacked)Usually 1–2
Stacked discountsMultiplied correctly, step traceOften added (overstated)
Effective vs naive %Shown side by sideRarely distinguished
Sales tax after discountOptional, 7 currenciesFrequently absent
Worked formulaShown for every resultUsually result only
Works offlineYes (PWA)No
Cost / signupFree, no signupOften ad-heavy or gated

AnyTool computes discounts locally and uploads nothing. Comparison as of June 2026.