PercentLab

Percentage Change Calculator

((new − old) / |old|) × 100.

From

Change %

((new − old) / |old|) × 100

Absolute change: 30

What you entered

From: 100To: 130

1
Absolute change
130 − 100= 30
2
Divide by the absolute original value
30 ÷ |100|= 0.3
3
Convert to a percentage
× 100= 30%

Result

Change %: 30

Going from 100 to 130 is a increase of 30%.

Percentage change between two values

Percentage change is the difference divided by the starting value. Negative values mean a decrease.

From	To	Absolute change	Percentage change
100	120	20	20.00%
100	80	-20	-20.00%
50	75	25	50.00%
80	100	20	25.00%
200	150	-50	-25.00%
1000	1250	250	25.00%

Rows one and two are the asymmetry everyone trips over: 100 to 120 is a 20% rise, but 120 back to 100 is a 16.67% fall, not 20%, because the base changed. Rows three and four make the same point - the same absolute change of 20 is 25% from a base of 80 but 20% from a base of 100. Always ask what the percentage is of. A 50% fall requires a 100% rise to recover, which is why investment losses are harder to undo than they look.

Relative change, not just the difference

Percentage change expresses how big a change is relative to the starting point — a $10 raise means a lot more to someone earning $50 than someone earning $5,000, and percentage change captures that context the raw difference alone misses.

Why use the absolute value of the original

Dividing by |old| instead of old keeps the sign of the result meaningful (increase vs. decrease) even when the starting value itself is negative.

Frequently asked questions

My rent went from $1,200 to $1,350 — what's the percentage change?

Percentage change = ((1350 − 1200) / 1200) × 100 = (150 / 1200) × 100 = 12.5% increase. Enter 1200 as the old value and 1350 as the new value above.

How is percentage change different from percentage difference?

Percentage change has a clear direction — one value is the 'before' and one is the 'after.' Percentage difference treats both values symmetrically (dividing by their average), which is useful when neither is a baseline, like comparing two cities' populations.

Can percentage change exceed 100%?

Absolutely. If a stock price goes from $10 to $35, that's a 250% increase. Percentage change can be any positive number for increases. For decreases, it maxes out at −100% (the value drops to zero).