Increase or decrease by percent

Add or take away a percentage: a 10% hike on a salary, 18% off a price, or find what the number was before the change.

Start with

ResultAnswer

50,000 increased by 12% is 56,000

Show working

Y = X × (1 + P ÷ 100)= 50,000 × (1 + 12 ÷ 100)= 56,000

Decimals

How it’s worked out

1To increase X by P%, multiply X by (1 + P ÷ 100). To decrease, multiply by (1 − P ÷ 100).
2To undo a change, divide instead: a price of 118 after 18% tax was 118 ÷ 1.18 = 100 before it.

Example

50,000 increased by 12% is 56,000.

Fill in any two of the three boxes and the third works itself out: what is P% of X, X is what percent of Y, or X is P% of what.

15% of 200 is 30

How much did something go up or down, in percent? Enter the old and new values, or a value and a change to find the other.

From 80 to 100 is a 25% increase

Compare two numbers when neither is the starting point. The difference is measured against their average, so the order doesn’t matter.

150 and 120 differ by 22.22%

Type a percent, a decimal or a fraction and see the other two. Fractions are simplified, so 37.5% becomes 3/8.

37.5% = 0.375 = 3/8

Find the sale price, how much you save, or what discount you’re really getting. Any two of price, discount and final price.

2,499 with 40% off is 1,499.40

Add GST to a price or take it out of an inclusive one, with the CGST and SGST split. Works for VAT and any sales tax too.

1,000 plus 18% GST is 1,180