About OG Calculators
◆ Our StoryWe build fast, free and privacy-friendly online calculators and web tools that anyone can use. No sign-ups, no downloads, just instant answers.
Calculators and web tools that keep everyday work simple
OG Calculators started with a simple idea: the tools people use every day to work out a percentage, a grade, a loan payment or a color code shouldn't be buried behind ads, logins or clunky interfaces. So we built a clean, modern home for all of them.
Every calculator and tool on the site runs entirely in your browser. Your numbers never leave your device, results appear instantly as you type, and the same experience works whether you're on a phone, tablet or desktop.
From students and teachers to developers, freelancers and families managing a budget, our goal is to give you accurate answers and show the working behind them, for free.
What we stand for
- Always free. No paywalls, no premium tiers, no limits.
- Private by design. Calculations happen locally in your browser.
- Accurate & clear. Real formulas with step-by-step results.
- Works everywhere. Responsive on every screen size.
Built around a few simple principles
Instant results
Everything calculates in real time as you type, with no page reloads, no waiting and no spinners.
Accurate by design
Proven formulas and carefully tested engines, with the working shown so you can trust the answer.
Privacy first
Nothing you enter is uploaded or stored on a server. Your data stays on your device, always.
Made for every device
A single, responsive design that feels right on phones, tablets and desktops alike.
Calculators and tools for real life
48 of them, grouped by what you are actually trying to work out. Every name below is a link.
Math Calculators
7 calculatorsPercentages, fractions, averages, ratios and full scientific expressions, each one worked out instantly with the method shown.
Geometry Calculators
8 calculatorsArea, volume, distance, slope and the right-angle maths behind real building work, with the formula and the working shown every time.
Finance Calculators
8 calculatorsWhat a loan really costs, what savings grow to and whether buying beats renting, worked out with real amortisation rather than rough estimates.
Health Calculators
4 calculatorsBMI, daily calories, pregnancy dates and ovulation timing, worked out with the standard formulas and every assumption stated plainly.
Everyday Calculators
9 calculatorsDates, grades, unit conversions, random draws and number-base conversions for the small jobs that come up every week.
Web Tools
12 toolsWriting, code and colour utilities that run entirely in your browser.
Have a question or an idea?
We'd love to hear from you. Feedback, bug reports and tool suggestions are all welcome.