About EasyPercentage
A free, ad-free suite of 13 percentage calculators. No signup. No tracking. All calculations run in your browser, instantly.
Why we built this
EasyPercentage was built by a software developer who kept hitting the same frustration: searching for a simple percentage calculation and landing on a page buried in ads, cookie popups, and auto-play videos — just to find a result that could have been computed in two seconds.
The goal was straightforward. Build the cleanest, most accurate set of percentage tools on the web and keep them permanently free. No ads. No signup. No limits. No data collection. Just the calculation you need, instantly, with the formula shown so you can verify it yourself.
Every tool on this site shows its working. We believe a calculator that explains its formula is more valuable than one that just shows a number — because understanding the formula means you never need the calculator again.
Our accuracy standards
Formulas and calculations
Every calculator uses standard mathematical formulas drawn from established references including financial mathematics texts, accounting standards, and educational curriculum guidelines. Formulas are displayed beneath every result so you can cross-check the working directly. All arithmetic runs client-side in JavaScript — there is no server involved, no rounding introduced by network calls, and no data transmitted.
Tax and VAT rates
Rate data on the Sales Tax Rates by State and VAT Rates by Country reference pages is sourced from official government publications: US state revenue department websites, the European Commission VAT Information Exchange System, and national tax authority guidance. Each page shows its update date and lists its primary sources. Rates are reviewed whenever legislative changes are announced, and each page carries an explicit update badge so you can judge whether to verify against the authoritative source before filing or invoicing.
What we check before publishing
Before any new calculator goes live, the formula is independently verified against at least two external references and tested against a set of known values. The worked example displayed in the formula explanation section is always computed manually first, then checked against the calculator output. Sub-pages that reference external data (tax rates, VAT rates, grade scales) include citations and update dates so the provenance of every figure is clear.
Reverse calculations
Every calculator on this site includes a reverse mode — enter the result to find one of the inputs. These inverse formulas are derived algebraically from the forward formula and verified independently. For example, the discount calculator can find the original price given a sale price and discount percentage, and the salary raise calculator can find the raise percentage given two salary figures.
Our principles
The tools
The suite currently covers 13 calculation types, each with its own dedicated page and reverse-calculation capability. Core tools include the percentage of a number calculator, percentage change calculator, discount calculator, tip calculator, markup calculator, grade calculator, sales tax calculator, and percent off calculator. Specialist tools cover VAT, salary raises, profit margins, discount plus tax, and stacked discounts. Reference data pages provide complete rate tables for US sales tax by state and VAT rates by country.
New tools are added when there is a genuine calculation need that existing pages don't cover well. The focus is always depth over breadth — a calculator that explains the formula, handles edge cases, and includes a worked example is more useful than a basic input-output form.
Privacy and data
EasyPercentage collects no user data. There are no analytics scripts, no advertising networks, no third-party tracking, and no cookies beyond what the browser itself manages locally for dark mode preference. The only external requests made by any page are the Google Fonts stylesheet (for DM Serif Display, DM Mono, and Syne) and nothing else. No calculation inputs are transmitted anywhere — all arithmetic runs in your browser's JavaScript engine. The full privacy policy is available if you need the formal version.
Embedding and reuse
All 13 calculators are available as free embeddable iframe widgets. Visit the embed page for code snippets you can drop into any website. No attribution is required, though a link back to EasyPercentage is appreciated. The embed code is self-contained — no additional scripts or stylesheets need to be loaded on your page.