All the tools you need, completely free

Calculators and developer utilities — mortgage, BMI, percentage, QR code, JSON and more. Use instantly, no account needed.

Free online calculators and developer tools that run in your browser

i-love-tools.com is a focused collection of utilities for the calculations and conversions people actually do every week — working out a mortgage payment, checking a BMI, splitting a restaurant bill, formatting a block of JSON, or generating a QR code for a link. Every tool is free, has no usage limit, and needs no account. There is nothing to install and nothing to sign up for: open the page, type your numbers, and read the answer.

Almost everything here runs entirely inside your browser. When you calculate a loan schedule or encode text to Base64, the computation happens on your own device using JavaScript — your inputs are never sent to a server, never logged, and never stored. That makes the tools fast (there is no network round-trip for the result), private by default, and usable even on a flaky connection.

What you'll find here

The catalog is deliberately small and maintained, rather than a dump of hundreds of half-working widgets. It is organized into three areas:

• Calculators — finance (mortgage, loan, compound interest, salary, ROI), health (BMI, BMR, calorie / TDEE), math (percentage), dates (age), construction (concrete, square footage), photography (aspect ratio), plus everyday helpers like discount and tip calculators.
• Developer tools — a JSON viewer / formatter / validator, a Base64 encoder and decoder, and a color-code converter that translates between HEX, RGB, RGBA, CMYK, HSV and HSL.
• QR codes — generate a scannable QR code for any website URL, ready to download and print.

The numbers behind each tool are explained

A calculator is only useful if you can trust the result and understand it. Every flagship tool on the site is accompanied by a written explanation of the formula it uses, worked examples you can follow by hand, the assumptions and edge cases that matter, and answers to the questions people most commonly ask. The BMI page, for instance, sets out both the metric and imperial formulas, the WHO category thresholds (including the lower cut-offs used for Asian populations), and when BMI is misleading for athletes and older adults. The mortgage and loan pages show the amortization math, not just a single monthly figure.

The goal is that you leave understanding why the answer is what it is — not just copying a number you have no way to check.

Why it's free

The site is supported by a small number of non-intrusive Google AdSense ads — no pop-ups, no interstitials, no auto-playing video, and no “Pro” tier hidden behind a paywall. Ads are only personalized if you explicitly consent through the cookie banner; until then, Google Consent Mode v2 keeps advertising and analytics cookies switched off. That revenue covers hosting and lets every tool stay genuinely free for everyone, with no artificial “3 uses left today” limits.

Frequently asked questions

Do I need to create an account? No. There is no log-in, no email collection, and no registration step anywhere on the site.

Are my inputs or files uploaded? For the in-browser tools, no — calculations and conversions happen locally on your device and the data never leaves it.

Is there a limit to how many times I can use a tool? No. Every tool is unlimited, every day, for every visitor.

Can I suggest a tool? Yes — new tools are prioritized largely from user requests. Use the contact page to send an idea, a bug report, or a correction to one of the explanations.