About PercentageChangeCalculators.com
PercentageChangeCalculators.com is a free hub of calculators and short guides for percentage change, percentage increase, percentage difference, reverse percentages, and related formulas. It's built and maintained by Ready Utilities.
What this site is for
Percentage math comes up constantly — prices, salaries, test scores, sales figures, lab measurements — and it's easy to get the formula slightly wrong, especially with negative starting values or when the difference between "change," "difference," and "points" actually matters. This site aims to give a straight answer fast: a working calculator plus the formula behind it, without extra steps.
How the calculators work
Every calculator on this site runs entirely in your browser. The numbers you enter are never sent to a server — the JavaScript on the page does the math locally and shows you the result. Formulas are checked against at least two independent, current sources before a page goes live, and every worked example shown on this site is recomputed independently before publishing, not just copied from a source. See each page's Sources section for the specific references used.
Cedrick Reese, Founder
I'm Cedrick Reese, a retired veteran and web developer who built PercentageChangeCalculators.com as part of Ready Utilities, my collection of free, user-friendly online tools. My journey began in the early 2000s with affiliate marketing and niche site development, which grew into a passion for creating practical digital utilities and calculators. After retiring, I earned a Computer Systems Technician certificate from UEI College, completed Electro-Mechanical Technologies at Tulsa Welding School, and finished the Carpentry program at Florida State College at Jacksonville. Today, I combine my technical background and craftsmanship by building furniture using traditional woodworking methods, gardening, and developing helpful online tools for users worldwide.