Percentage Change Calculator

This is directional: one value is treated as the starting point and the other as where it ended up, so the order matters and can flip the sign. A move from 50 to 75 is a +50% change, but the same two numbers the other way (75 to 50) is a −33.3% change, not the same number reversed. If neither value is really a "before" — you're comparing two independent measurements — use Percentage Difference instead, which gives the same result regardless of order.

It's rejected rather than calculated. Percentage change from zero is mathematically undefined — any nonzero result would be an infinite percent increase — so the tool asks for a nonzero starting value instead of showing Infinity.