About CalcDesk
CalcDesk is a free set of 22 everyday calculators — finance, health, maths and unit conversion — built to give you a straight answer and then explain where that answer came from.
Most calculator sites hand you a number and stop. We think the number is the least interesting part. Every tool on this site publishes the formula it uses, a worked example with real figures, and an honest list of the cases where the result will mislead you. The BMI page tells you BMI was designed for populations and breaks down for muscular people. The ROI page tells you why a raw return figure flatters a long holding period. That is the part most people actually need.
How the tools are built
The calculators use published, named formulas rather than anything we invented: WHO adult bands for BMI, Mifflin–St Jeor for calorie and TDEE estimates, Devine and Robinson for ideal-weight ranges, and standard annuity amortisation for loan and mortgage payments. Where a field has genuine disagreement — hydration targets, "ideal" weight — we say so on the page instead of picking one number and presenting it as settled.
Everything runs as plain JavaScript in your browser. Your inputs are never transmitted to us, stored, or logged. There is no account to create, nothing to install, and no upload step — which is why the health and salary figures you type here stay on your own machine.
Who publishes CalcDesk
CalcDesk is published and maintained by Bloom Agency, a digital studio that builds websites, SaaS products and secure digital tooling for small and medium businesses. You can find our main practice at bloomagency.pro.
CalcDesk started as an internal utility — we kept rebuilding the same loan and margin calculations for client projects — and we published it because the explanations turned out to be more useful than the arithmetic.
Corrections
If a calculator returns a wrong result, or an explanation is inaccurate or out of date, tell us and we will fix it. Email hello@calcdesk.cc with the tool name and the figures you entered, and we will reproduce it. Corrections to the underlying maths are treated as urgent; we would rather hear about it than have the number quietly stay wrong.
Nothing here is financial, medical or legal advice. These are estimates to help you think, and important decisions deserve a professional who knows your situation.