About CalciTools
CalciTools is a free library of online calculators for finance, math, health, and science. Our goal is simple: give you an answer you can trust, with the working shown — not just a number.
How we build our calculators
Every calculator is built around a standard, established formula — the same math used by banks, textbooks, and professional references. We don't invent methods. Where a calculation has a widely accepted convention (for example, reducing-balance EMI for loans, or PITI for mortgages), we follow it, and we state the formula on the page so you can check our working.
How we verify accuracy
Before a tool goes live, its math is tested against hand-computed and reference examples. Financial tools are checked against known worked examples; scientific and health tools against their source formulas. Each calculator page includes a worked example and the underlying formula so you can confirm the result yourself. If you ever spot a discrepancy, we want to hear about it — see our contact page.
How we keep tools current
Calculators that depend on changing figures — tax brackets, contribution limits, typical interest rates — are reviewed and updated when those figures change. Pages show when they were last updated.
Who writes our content
Our guides and calculator explanations are written and reviewed by the CalciTools Editorial team. We aim for clear, accurate, jargon-free explanations that help you understand the math, not just get a number.
Important note
CalciTools provides educational tools and information, not professional financial, medical, legal, or tax advice. For decisions that matter, please confirm results with a qualified professional.