57 free tools · no sign-up
Small, fast tools for everyday tasks
Calculators and utilities that run entirely in your browser. Nothing you type is uploaded, and there's nothing to install.
Start here
A cross-section of the catalogue — money, health, home, and data.
Mortgage Calculator
Estimate your monthly mortgage payment and long-term interest cost.
Debt Payoff Planner
Compare avalanche and snowball payoff time and estimated interest.
BMI Calculator
Calculate adult BMI with metric or US measurements.
Fence Calculator
Estimate posts, rails, sections, and pickets for a fence run.
JSON Formatter and Validator
Validate, format, minify, and sort JSON in your browser.
Recipe Cost Calculator
Estimate recipe usage cost, checkout cost, and cost per serving.
Browse by category
Every tool lives in one category, so related work stays together.
Built for practical answers
Your input stays in the browser
Tools calculate client-side. Balances, measurements, and pasted text are not sent to a server to be processed.
Fast, static pages
Every page is prebuilt. There is no framework to download and no account wall between you and the answer.
Assumptions stated plainly
Each tool explains what it models and where the estimate stops being reliable, rather than presenting a number without context.
About Tools by Leaf
Is Tools by Leaf free to use?
Yes. Every tool on Tools by Leaf is free, with no account required.
Do I need to create an account?
No. Nothing you enter is saved, and there's no sign-up.
Where do calculations happen?
In your browser. Tools by Leaf's tools run client-side, so your inputs aren't sent to a server to be calculated.
Is Tools by Leaf still being added to?
Yes — new tools are added regularly, and existing ones get corrections and improvements.