Every answer shows its work
Most calculator sites give you a number and nothing else. Here, every calculator comes with its derivation: where the formula comes from, what each term means, a worked example, and the mistakes people commonly make. If a formula is empirical, like a body-fat estimate fitted to a study population, the page says what data it came from and where it stops being reliable.
The name is a nod to the Library of Alexandria, which tried to collect the world's knowledge in one place. This site tries to do the same for the everyday formulas people reach for in labs, kitchens, classrooms and workshops.
Who it's for
Students checking homework, scientists making up a buffer, bakers scaling a recipe, engineers sizing a resistor, and anyone else who needs a quick, trustworthy calculation and wants to understand it.
Accuracy
Each formula is checked against published sources, which are listed on its page, and each calculator is covered by automated tests. Mistakes still happen. If you find one, email hello@calculatorofalexandria.com and it will be fixed.
Health and medical calculators are for education. They are not medical advice, and they don't replace a clinician's judgment.
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