About Calcora

Calcora is a free collection of calculators for the numbers that come up in everyday life — what a loan actually costs, whether a weight is in a healthy range, how many days until a due date, what a tip should be. Every tool runs entirely in your browser: no account, no email wall, no watching a spinner while a server crunches your numbers.

What's here

The site is organized into five groups, currently covering 43 calculators:

5Cultural Pulse — timely, of-the-moment cost calculators
14Financial — loans, mortgages, retirement, tax, salary, sales tax, and more
9Health & Fitness — BMI, calories, body fat, pregnancy, pace
11Math & Utilities — scientific calculator, statistics, grading, networking, passwords
4Dates & Time — age, durations, hours, scheduling

How the calculators are built

Each calculator uses a standard, published formula for its category — the amortization formula for loans, the Mifflin–St Jeor equation for calorie needs, the US Navy circumference method for body fat, current IRS bracket figures for income tax, and so on. Before a calculator goes live, its output is checked against known reference values and edge cases (zero-interest loans, overnight time spans, negative fractions) so the math holds up, not just the common case.

Financial and tax figures are dated because they change — tax brackets shift yearly, for instance — and calculators that depend on them note the year they reflect. If you spot a figure that's gone stale or a result that looks wrong, the Contact page is the fastest way to flag it.

Why it's free

Calcora is supported by advertising rather than subscriptions or accounts. That's the trade that keeps every calculator open to anyone without a paywall or a login. Ads run through Google AdSense; how that works and what data it involves is covered in the Privacy Policy.

Feedback

Requests for a calculator that isn't here yet, corrections, or general feedback are all welcome — see the Contact page.