We build calculators we’d actually want to use

Why we made this

Most calculator sites hide the number you want inside a wall of text, throw a pop-up in your face before you can type, and never show you the math. We got tired of it. 4calcs puts the result at the very top, keeps the interface clean, and explains every formula in plain English so you can check it yourself.

How we calculate

Every calculator runs entirely in your browser — nothing you type into a calculator is sent to a server. (The only thing that reaches us is a message you choose to send through the contact form.) We use standard, published formulas: amortization for loans and mortgages, the 2026 IRS federal brackets for take-home pay, BLS CPI data for inflation, and CDC/WHO ranges for BMI. Each page shows the exact formula and a worked example under the result, and our Methodology page lists every source.

What we are not

We are not a bank, a lender, a broker, a doctor, or a tax advisor. 4calcs gives educational estimates to help you understand your options and ask better questions. For decisions that matter, talk to a licensed professional. If we ever add a partner link such as “See local rates”, it will be clearly marked and will never interrupt your calculation.

In numbers: 28 calculators, every one running entirely in your browser, free to use, with no pop-up between you and the result.

Who is behind 4calcs

4calcs is run by Jairo Tunisse, who builds the calculators and maintains the data behind them. Guides go through human review before they are published. Our editorial policy explains how pages are sourced, maintained, updated and corrected. Questions or corrections are welcome through the contact page.