Numarly

Discount Stacking Calculator

Apply multiple successive discounts and find the true effective discount.

Successive Discounts (%)

What is it?

This calculator applies multiple discounts one after another (each on the already-reduced price) and shows the true effective discount — which is always less than simply adding the percentages together.

Formula

Final Price = Original Price × (1 − d₁%) × (1 − d₂%) × ... × (1 − dₙ%)

Formula Explanation

Each successive discount is applied to the price after the previous discount, not to the original price. This is why two stacked discounts of 20% and 10% don't add up to a 30% discount — the 10% only applies to the already-reduced amount, resulting in an effective discount of 28%.

Example Calculation

A $2,000 item with 20% off, then an additional 10% off: first drops to $1,600, then to $1,440 — an effective discount of 28%, not the 30% you'd get by simply adding the percentages.

How to Use

  1. Enter the original price.
  2. Add each discount percentage in the order it's applied.
  3. Add more discounts to stack as many as needed.
  4. Read off the final price and the true effective discount percentage.

Benefits

  • Reveals the real effective discount instead of the misleading sum of percentages.
  • Shows the price after each individual discount step for full transparency.
  • Works for any number of stacked discounts, coupons, or promotions.

Use Cases

  • Retailers calculating the true price after stacking a seasonal sale with a coupon code.
  • Shoppers checking whether a 'combined 40% off' claim actually matches applying two separate discounts.
  • Businesses setting promotional pricing rules that combine multiple discount types.

What Your Result Means

The effective discount percentage is always less than or equal to the sum of the individual discount percentages — the gap grows larger as more discounts are stacked. This is the number to use for actual pricing and margin decisions, not the naive sum.

Tips

  • Order doesn't affect the final price — a 20% then 10% discount gives the same result as 10% then 20%.
  • Watch for marketing claims that add discount percentages together (e.g. '20% + 10% = 30% off') — the real effective discount is always lower.
  • Use this to sanity-check margin impact before approving stacked promotional discounts.

Common Mistakes

  • Adding discount percentages together instead of applying them successively, which overstates the actual discount.
  • Assuming stacking order changes the result — mathematically, multiplication is commutative, so order doesn't matter.
  • Forgetting that very large stacked discounts (e.g. three 50% discounts) can shrink the price much faster than expected.

FAQs

Why isn't 20% + 10% equal to 30% off?

Because the second discount applies to the already-discounted price, not the original price — the compounding effect always produces a smaller total discount than simple addition.

Does the order of discounts matter?

No, mathematically the final price is the same regardless of which discount is applied first, since multiplication is commutative.

Is a store advertising 'up to 50% off, plus an extra 20%' using this same logic?

Yes, this is a common stacking scenario — this calculator shows you exactly what the combined discount really works out to.

This tool assumes discounts are applied sequentially as percentages of the current price, which is the standard method for stacked or successive discounts.

Last updated: July 26, 2026