Reduce a number by a percentage. Useful for discounts, falling value, price cuts, and anything that shrinks by a set percentage.
The percentage is applied to the original value to find the amount of the decrease.
That amount is subtracted from the original value.
A decrease of 100% reduces the number to zero; anything beyond that goes negative.
Decrease amount: Value × Percent ÷ 100
Result: Value − Decrease
An item priced at ₹200 is reduced by 15%.
Original price: ₹200
Decrease: 15%
Find the decrease: 200 × 15 ÷ 100 = 30
Subtract it: 200 − 30 = 170
Answer: ₹170 (a reduction of ₹30)
A percentage decrease calculator starts from an original value and cuts it by a given percentage. It shows the amount removed and what is left. When a pair of shoes marked ₹2,499 is on a 30% off sale, it tells you the rupee discount and the price you will actually pay at the counter.
Shoppers use it during festive sales, businesses use it to plan markdowns, and households use it to see what a cut in electricity usage or a lower phone bill means in rupees. It is also used for depreciation of a vehicle's value, for reduced attendance or production, and for any figure that shrinks by a known share of where it began.
1. Write down the original value V and the percentage decrease p.
2. Find the amount of the decrease: decrease = V × p ÷ 100.
3. Subtract it: new value = V − decrease.
4. Or use the retention factor directly: new value = V × (1 − p ÷ 100).
5. For two decreases in a row, multiply the retention factors: V × (1 − p₁ ÷ 100) × (1 − p₂ ÷ 100).
6. Check that the new value lies between 0 and V when p is between 0 and 100.
Cutting p% means keeping (100 − p)%. A 30% discount keeps 70% of the price, so the sale price is 0.70 × the marked price. This view is often faster than finding the discount and subtracting it. It also explains the limits. A 100% decrease leaves nothing, and anything above 100% makes the result negative, which is meaningful for quantities like profit but not for prices. The calculator does not stop you, so read a negative answer as a sign that the percentage was too large for the situation.
Offers such as 'flat 20% plus an extra 10% on the discounted price' apply the second cut to an already reduced value. The combined factor is 0.80 × 0.90 = 0.72, which is a 28% total discount, not 30%. The same logic makes a 50% fall followed by a 50% rise leave you at 75% of the start. Because each percentage works on a different base, equal percentage moves in opposite directions never cancel. Only the factors multiply cleanly.
If you know only the reduced value and the percentage, divide by the retention factor: original = new ÷ (1 − p ÷ 100). An item selling at ₹1,749.30 after a 30% cut was originally 1,749.30 ÷ 0.70 = ₹2,499. Adding 30% of ₹1,749.30 back gives about ₹2,274, which is wrong because the discount was taken from the bigger number. Retailers also quote discounts on the MRP, so compare the base printed on the tag before trusting a percentage.
Kavya sees running shoes with a marked price of ₹2,499 in a festive sale that offers 30% off.
Find the decrease: 2499 × 30 ÷ 100
Subtract it from the original: 2499 − 749.7
Answer: Result after decrease 1,749.3; Original value 2,499; Amount removed 749.7
Adding two successive discounts, such as 20% and 10%, as if they made 30% off.
Reversing a discount by adding the same percentage back to the sale price.
Ignoring that GST may be charged on the discounted price, so the bill differs from the tag calculation.
Describing a fall from 60 to 45 as 33% because the difference was divided by the new value instead of the original.
Working out the sale price during Diwali, Republic Day or end-of-season sales.
Estimating a car or two-wheeler's resale value after a stated yearly depreciation.
Planning a markdown on slow-moving stock in a retail shop.
Showing how much a household saves when the electricity or water bill falls by a known share.
Reporting a fall in production, attendance or sales against a base period.
Why doesn't a 50% rise followed by a 50% fall return to the start?
Each percentage is worked out on a different starting number. 100 rising by 50% gives 150. But 150 falling by 50% gives 75, not 100 — because the fall is worked out on the bigger number.
How do I find the original price before a discount?
Divide by (1 − percent/100). An item now priced at ₹170, after a 15% discount, was originally 170 ÷ 0.85 = ₹200.