Percentage Increase Calculator

A salary review comparing this year's figure against last year's, a business tracking revenue growth quarter over quarter, or a shopper comparing a listed price against what an item cost previously are all asking the identical underlying question — how big is the change, expressed as a proportion of the value it started from — even though the numbers and context differ completely each time. The formula is the same regardless: divide the difference between the two values by the original value, then express that as a percentage, which is exactly what this mode computes and shows the working for, with the actual entered numbers substituted directly into the formula so the arithmetic can be double-checked at a glance.

There is no need for a separate "percentage decrease" mode alongside this one, because a decrease is mathematically the identical formula applied to a new value smaller than the original — the result comes out negative rather than needing a different calculation entirely. Entering a new value below the original one here produces the percentage decrease automatically, with the negative sign making the direction of the change immediately clear, and the same formula and working shown either way regardless of which direction the change happens to run.