Who runs this site
Hi, I'm Sam Alex, a civil engineer based in Australia. I started Metric Unit Calculator because so much of my working day is quick calculations such as loads, areas, volumes, flow rates and unit conversions. The tools I found online were often cluttered, hid the formula, or mixed up metric and imperial units.
Outside engineering I'm a husband and a dad of three, so I also know the everyday side of calculations: budgets, loan repayments, fuel, recipes and homework help. This site is my attempt to put all of those in one clean, free place.
What you'll find here
The site covers construction and engineering, physics, mathematics, statistics, chemistry, biology, agriculture, finance, sport and unit conversions. Every calculator is free to use, needs no account, and runs in your browser.
How the formulas are checked
- Standard formulas only. Each calculator uses a published, textbook relationship (for example F = m × a, or BMI = mass ÷ height²) rather than a custom model. Physical constants follow recognised references such as NIST.
- Units are stated on every input. Each field shows the unit it expects, and results show their unit, so you can see exactly what is being calculated.
- The working is shown. Under each result, the "How this result was calculated" section shows the formula, your values substituted in, and the evaluated answer, so you can check it by hand.
- Tested with known answers. Calculators are checked against worked examples with known results before they are published. For example, 10 kg × 9.81 m/s² must return 98.1 N.
- Reader feedback is reviewed. Every calculator has a Feedback button. I read every message, and when someone reports an error I check it and correct the calculator.
Important limits
These calculators are for education, planning and quick estimates. They are not a substitute for professional advice. For structural, electrical, medical, financial or legal decisions, have the result checked by a qualified professional who knows your situation. That is the same standard I apply in my own engineering work.
Get in touch
Found a mistake, or want a calculator that isn't here yet? Use the contact page or the Feedback button on any calculator. Suggestions from readers shape what gets built next.