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    Discount Calculator

    Calculate sale prices, savings, and stack multiple discounts. Supports GBP, USD, and EUR.

    Free to use. Runs in your browser.

    Enter the original price and discount percentage to instantly see the sale price and how much you save.

    Stack multiple discounts, supports GBP, USD, and EUR.

    Discount Calculator

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    How Stacked Discounts Actually Work

    Here's the trap most shoppers fall into: a 30% discount plus a 20% discount does NOT equal 50% off. Discounts stack multiplicatively, not additively. Each discount applies to the already-reduced price, not the original.

    Take a £100 item with 30% off then 20% off. First discount: £100 × 0.70 = £70. Second discount: £70 × 0.80 = £56. You saved £44, that's 44% off, not 50%. The difference grows with bigger discounts and more layers.

    The maths: multiply the remaining percentages together. 70% × 80% = 56%, meaning you pay 56% of the original price. The effective discount is 100% − 56% = 44%. This calculator handles all of this automatically, even with three or four stacked codes.

    Discount Equivalents at a Glance

    DiscountYou PayOn £100Equivalent Fraction
    10% off90%£909/10
    20% off80%£804/5
    25% off75%£753/4
    33% off67%£672/3
    40% off60%£603/5
    50% off50%£501/2
    75% off25%£251/4

    What this means for you: The fraction column is useful for quick mental maths. "25% off" means you pay three-quarters. "33% off" means you pay two-thirds. If a £60 item has 25% off, you're paying three-quarters: £60 × ¾ = £45.

    Common Stacked Discount Results

    First DiscountSecond DiscountEffective TotalNOT the Same As
    10%10%19% off20% off
    20%10%28% off30% off
    20%20%36% off40% off
    30%20%44% off50% off
    40%20%52% off60% off
    50%20%60% off70% off

    What this means for you: That "extra 20% off sale items" at the checkout isn't as generous as it sounds. On a 30% sale item, you're getting 44% off total, not 50%. Still a good deal, but worth knowing the real number before you buy.

    Pricing Psychology You Should Know

    Anchor Pricing

    When you see "Was £200, Now £120," the £200 is the anchor. It makes £120 feel like a bargain, even if the item was never widely sold at £200. Always research the typical price before assuming a discount is genuine.

    Charm Pricing

    £9.99 instead of £10 works because your brain processes the first digit first. Studies show items priced at .99 outsell identical items at round numbers by 24%. You know it's a trick, and it still works.

    "Up to 70% Off"

    The "up to" is doing all the heavy lifting. It means one item somewhere has 70% off. The average discount across the sale is usually much lower, typically 20 to 30%. Check the actual discount on the specific item you want.

    Buy One Get One "Free"

    BOGOF is mathematically identical to 50% off when you buy two, but it makes you buy more than you planned. If you only need one, you're spending money on an item you didn't want. The best discount is on the thing you were already going to buy.

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    How to use this tool

    1

    Enter the original price

    2

    Add one or more discount percentages

    3

    See the final price and total savings

    Common uses

    • Checking how much you save during seasonal sales
    • Stacking coupon codes to find the true final price
    • Comparing discounts across retailers before buying
    • Working out trade or wholesale discount pricing
    • Verifying marked-down prices at checkout

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    Frequently Asked Questions

    How does the discount calculator work?
    Enter the original price and one or more discount percentages. The calculator applies them sequentially and shows the final price, total savings, and effective discount percentage. Supports GBP, USD, and EUR.
    Can I stack multiple discounts?
    Yes. Click 'Add Discount' to layer multiple discounts. They're applied in order, each discount reduces the already-discounted price. A 30% + 20% discount gives 44% off total, not 50%.
    Why don't stacked discounts add up to their sum?
    Discounts stack multiplicatively, not additively. Each discount applies to the already-reduced price. With 30% then 20%: you pay 70% of the original, then 80% of that. 0.70 × 0.80 = 0.56, so you pay 56%, a 44% effective discount, not 50%.
    Does the order of stacked discounts matter?
    No, the final price is the same regardless of order. 30% then 20% gives the same result as 20% then 30%. Multiplication is commutative: 0.70 × 0.80 = 0.80 × 0.70. The intermediate prices differ, but the end result is identical.
    How do I calculate the discount percentage from original and sale price?
    Subtract the sale price from the original, divide by the original, multiply by 100. If an item dropped from £80 to £60: (80 − 60) ÷ 80 × 100 = 25% off. Our Percentage Calculator can do this in the 'Percentage Change' mode.
    How do I work out the original price before a discount?
    Divide the sale price by (1 − discount rate). If you paid £56 after a 30% discount: £56 ÷ 0.70 = £80. Don't add 30% to £56, that gives £72.80, which is wrong because the 30% applies to the original base, not the discounted one.
    Is 'buy one get one free' the same as 50% off?
    Mathematically yes, if you buy two. You pay for one and get two, so each item effectively costs 50% of the original. But BOGOF makes you buy more than you planned. If you only need one, you're spending money on an unwanted second item. The best discount is on something you were already going to buy.
    How do retailers trick you with anchor pricing?
    Anchor pricing shows a high 'was' price next to the current price to make the discount feel larger. 'Was £200, now £120' makes £120 feel like a steal, even if the item was rarely sold at £200. Always research the typical market price before assuming a discount is genuine.
    What does 'up to 70% off' actually mean?
    It means one item somewhere in the sale has 70% off. The average discount is usually 20 to 30%. 'Up to' is doing all the heavy lifting. Always check the specific discount on the item you actually want, the headline number is marketing, not a guarantee.
    Can a discount ever exceed 100%?
    No, a discount above 100% would mean the retailer pays you to take the item. In practice, the maximum discount is 100% (free). If you see stacked discounts that seem to total over 100%, remember they're multiplicative: even a 90% + 90% stack only gives 99% off (0.10 × 0.10 = 0.01 = 1% remaining).
    Does this support different currencies?
    Yes, toggle between GBP (£), USD ($), and EUR (€) using the currency buttons. The calculations work identically regardless of currency; only the symbol changes.
    How do I spot a fake discount?
    Compare the 'sale' price against other retailers, check price history tools like CamelCamelCamel (Amazon) or PriceSpy, and be sceptical of vague 'was' prices. In the UK, the item must have been sold at the higher price for 28 consecutive days in the previous 6 months for the 'was' price to be legal.

    Results are for general informational purposes only and should be checked before use. They are not professional advice. See our Disclaimer and Terms of Service.