Percentage Calculator

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percent discount, calculate price after discount

Percent discount: calculate the final price and the savings

A percentage discount takes a slice off the price: 15% off 200 leaves 170, because 200 × 0.85 = 170. The calculator opens in the "decrease" mode, with 200 and 15% already filled in, and shows the final price, the amount saved (30) and the factor used, 0.85.

Discount factor, savings and discounts in sequence

The discount factor is 1 − p ÷ 100: 20% off is × 0.80, 30% is × 0.70, 12.5% is × 0.875. With it, 80 with 20% off costs 64; 1,200 with 12.5% off costs 1,050; and a 349.90 television with 30% off costs 349.90 × 0.70 = 244.93, saving 104.97. The calculator separates the two numbers that matter, what you pay and what you save, and keeps the calculation exact until the last step: rounding to cents only happens on display.
Discounts in sequence are the classic trap. A 20% discount followed by another of 10% on 250 is not worth 30%: the first brings it to 200 (250 × 0.8) and the second applies to that value, reaching 180 (200 × 0.9). The total discount is 28% (factor 0.72), not the 30% of the sum, a difference of 2 percentage points. For this calculation use the successive mode, which computes the total factor and compares it with the naive sum. The order of the discounts does not change the final result, only the intermediate value.
To decide whether a discount is worth it, always compare the final price, not the advertised percentage. A 349.90 item with 30% off comes to 244.93; another at 279.90 with 15% off comes to 237.92 (279.90 × 0.85), and is cheaper even with the smaller percentage. If you only know the price after the discount and want the list price, do not add the percent back: that is another calculation, handled by the original value mode. And if the missing data is the percent, calculate it from the change between the old and the new price.

Calculations checked by the calculator engine

200 with 15% off

Input: 200 − 15%
Expected output: 170

Factor 0.85; saves 30.

80 with 20% off

Input: 80 − 20%
Expected output: 64

Factor 0.80; saves 16.

349.90 with 30% off

Input: 349,90 − 30%
Expected output: 244,93

Factor 0.70; saves 104.97.

1,200 with 12.5% off

Input: 1.200 − 12,5%
Expected output: 1.050

Factor 0.875; saves 150.

Two discounts: 20% and 10% on 250

Input: 250 × 0,8 × 0,9
Expected output: 180 (−28%)

Total factor 0.72, not 0.70.

Full tool FAQ

How do I work out a percentage in my head?

Start with 10%, which is the value divided by 10, and build the rest from it: 1% is dividing by 100, 5% is half of 10%, 20% is double 10%, 25% is dividing by 4 and 50% is dividing by 2. For 15% of 80, take 10% (8) plus 5% (4), which is 12. For 35% of 200, add 30% (60) and 5% (10), which is 70. If the numbers are awkward, swap the order: 8% of 50 equals 50% of 8, which is 4.

How do I calculate X% of a value?

How do I find what percent one number is of another?

How do I calculate a percentage increase or discount and the final value?

How do I calculate the percent change between two values?

How do I find the original value before a discount or increase?

Why don't two successive discounts add up? What is 20% and then 10%?

What is the difference between a percentage point and a percent?

What is the difference between margin and markup, and how do I convert?

How do I calculate a tip and split the bill between people?

How do I calculate a change repeated over several periods?

Does the calculator round? Why doesn't 0.30000000000000004 show up?

Frequently asked questions

How do I calculate the price with 30% off?

Multiply the price by 0.70. For 349.90, that gives 244.93. Or work out 30% of the price (104.97) and subtract: 349.90 − 104.97 = 244.93. The two calculations are equivalent.

Do two discounts of 20% and 10% add up to 30%?

No: they give 28%. The second applies to the already reduced price (250 becomes 200 and then 180). The calculator shows the difference in the successive mode.

Which discount is better, 30% or 15% on another product?

Compare the final price, not the percentage. A 349.90 item at 30% comes to 244.93; a 279.90 one at 15% comes to 237.92, which is cheaper.

Next steps

Discount factor, savings and discounts in sequence

The discount factor is 1 − p ÷ 100: 20% off is × 0.80, 30% is × 0.70, 12.5% is × 0.875. With it, 80 with 20% off costs 64; 1,200 with 12.5% off costs 1,050; and a 349.90 television with 30% off costs 349.90 × 0.70 = 244.93, saving 104.97. The calculator separates the two numbers that matter, what you pay and what you save, and keeps the calculation exact until the last step: rounding to cents only happens on display.

Discounts in sequence are the classic trap. A 20% discount followed by another of 10% on 250 is not worth 30%: the first brings it to 200 (250 × 0.8) and the second applies to that value, reaching 180 (200 × 0.9). The total discount is 28% (factor 0.72), not the 30% of the sum, a difference of 2 percentage points. For this calculation use the successive mode, which computes the total factor and compares it with the naive sum. The order of the discounts does not change the final result, only the intermediate value.

To decide whether a discount is worth it, always compare the final price, not the advertised percentage. A 349.90 item with 30% off comes to 244.93; another at 279.90 with 15% off comes to 237.92 (279.90 × 0.85), and is cheaper even with the smaller percentage. If you only know the price after the discount and want the list price, do not add the percent back: that is another calculation, handled by the original value mode. And if the missing data is the percent, calculate it from the change between the old and the new price.

Calculations checked by the calculator engine

200 with 15% off

Input: 200 − 15%
Expected output: 170

Factor 0.85; saves 30.

80 with 20% off

Input: 80 − 20%
Expected output: 64

Factor 0.80; saves 16.

349.90 with 30% off

Input: 349,90 − 30%
Expected output: 244,93

Factor 0.70; saves 104.97.

1,200 with 12.5% off

Input: 1.200 − 12,5%
Expected output: 1.050

Factor 0.875; saves 150.

Two discounts: 20% and 10% on 250

Input: 250 × 0,8 × 0,9
Expected output: 180 (−28%)

Total factor 0.72, not 0.70.

Full tool FAQ

How do I work out a percentage in my head?

How do I calculate X% of a value?

How do I find what percent one number is of another?

How do I calculate a percentage increase or discount and the final value?

How do I calculate the percent change between two values?

How do I find the original value before a discount or increase?

Why don't two successive discounts add up? What is 20% and then 10%?

What is the difference between a percentage point and a percent?

What is the difference between margin and markup, and how do I convert?

How do I calculate a tip and split the bill between people?

How do I calculate a change repeated over several periods?

Does the calculator round? Why doesn't 0.30000000000000004 show up?

Frequently asked questions

How do I calculate the price with 30% off?

Multiply the price by 0.70. For 349.90, that gives 244.93. Or work out 30% of the price (104.97) and subtract: 349.90 − 104.97 = 244.93. The two calculations are equivalent.

Do two discounts of 20% and 10% add up to 30%?

No: they give 28%. The second applies to the already reduced price (250 becomes 200 and then 180). The calculator shows the difference in the successive mode.

Which discount is better, 30% or 15% on another product?

Compare the final price, not the percentage. A 349.90 item at 30% comes to 244.93; a 279.90 one at 15% comes to 237.92, which is cheaper.