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About Qalkulator

Qalkulator is a collection of free online calculators for money, health, math, dates and unit conversion. The aim is simple: give the right answer quickly, and show how it was reached.

Qalkulator is operated by Piksel & Co Digital LLC, a company registered in Delaware, USA.

How each calculator is built

  • Published formulas. Calculators use standard, documented methods — the amortization formula for loans, the Mifflin-St Jeor equation for BMR, exact international definitions for unit conversion. Each page names its formula and lists sources where a method comes from an outside authority.
  • Tested code. Every calculation is a separate function with automated tests covering normal values, edge cases such as zero and leap years, and invalid input. A calculator is not published until those tests pass.
  • Money in whole cents. Loan schedules are worked out the way lenders do: interest is rounded to the cent each period, so the totals always add up.
  • The working, shown. Most results include a “Show the working” panel with the formula filled in with your numbers, so you can check the result or follow it by hand.

Reviews and corrections

Each calculator page shows the date its content and formulas were last reviewed. If you think a result is wrong, tell us with the inputs you used — every report is checked against the formula and the tests.

What Qalkulator is not

Calculators give estimates for planning and learning. They are not financial, tax, legal or medical advice; see the disclaimer.

Updated September 19, 2026