How to Use the Ratio Change Calculator
When comparing two percentage values — like a conversion rate, market share, or survey result — it's easy to confuse the simple point difference with the relative rate of change. This calculator takes a before and after ratio and shows both figures together, plus a bar visualization of the shift.
A percentage point (pp) change is just the plain difference between two values, while a relative percent change shows how much the value grew or shrank compared to the original. If a conversion rate rose from 10% to 25%, that's a 15pp increase and also a 150% increase — two very different-sounding numbers describing the same shift. When the before value is 0, the relative rate is mathematically undefined, so only the point difference is shown in that case.
Frequently Asked Questions
A percentage point is the simple difference between two ratios, while percent shows the relative change versus the original value. Going from 10% to 20% is a 10pp increase and a 100% increase.
Relative change divides by the before value, so dividing by zero is undefined. Use the percentage point difference instead in that case.
Yes, negative values representing a decrease are supported and calculated the same way.