Subtract the old value from the new value, divide by the old value, and multiply by 100. Going from 80 to 100 is (100 - 80) / 80 = 0.25, a 25 percent increase. Going from 100 down to 80 is (80 - 100) / 100 = -0.20, a 20 percent decrease. A free calculator handles the signs and the division for you instantly.
Free percentage change calculator. Find the percent increase or decrease between two numbers and the absolute difference, with the direction shown.
Open Percentage Change Calculator → Free toolFree percentage increase and decrease calculator. Find the percent change between two numbers and the new value after applying a percentage.
Open Percentage Increase and Decrease Calculator →Percent change = ((new - old) / old) x 100. The division is always by the OLD value, which is the detail people get wrong. From 80 to 100 the change is 20 on a base of 80, so 25 percent up. From 100 to 80 the change is -20 on a base of 100, so 20 percent down. Same two numbers, different percentages, because the base changed.
If a rate moves from 40 percent to 50 percent, it rose 10 percentage points, but as a relative change it rose 25 percent, because 10 / 40 = 0.25. Mixing the two up is one of the most common statistics mistakes in headlines. A percentage change calculator gives you the relative figure; the point difference is just plain subtraction.
Because the base differs. The increase is measured against 80 (20 / 80 = 25 percent) while the decrease is measured against 100 (20 / 100 = 20 percent).
Points are plain subtraction, percent change is relative. Moving from 40 percent to 50 percent is 10 percentage points but a 25 percent relative increase.
The same one: ((new - old) / old) x 100. When the new value is smaller the result is negative, which reads as a decrease.