Tiny Tool is run by Alex Carter, an independent developer. It started the way most useful things do: with a recurring annoyance. Whether it was estimating a shipping quote before invoicing a client, checking whether a loan offer actually made sense, converting a recipe, or figuring out a grade needed on a final exam — the answer always required the same handful of formulas, and the tools that promised them were either black boxes, buried behind signups, or quietly wrong.
So this site was built: one place with free, no-signup calculators that show their math. No paywalls, no “pro” upgrade, no mystery coefficients.
How the tools are built
Every calculator on Tiny Tool follows the same routine before it goes live:
- Source the formula from its primary origin. Tax tools start from IRS publications and forms; business and trade tools from official rate tables and standards bodies; health and fitness tools from peer-reviewed equations (with the citation named on the page).
- Cross-check against at least two independent references — textbooks, government guidance, or established industry references — and reconcile any differences explicitly rather than averaging them away.
- Test with worked examples and edge cases: zero values, negative inputs, unit boundaries, and the largest realistic values each field accepts.
- Document assumptions on the page itself. Each tool carries a “Formula and Logic” section and “Practical Notes” that state what the calculator assumes, what it does not take into account, and where its results stop being reliable.
When a rule or rate changes (tax brackets, filing thresholds, standards), the affected tools are revisited and the page is updated. If you spot an error, it is treated as a bug: report it and it gets fixed at the formula level, not just the copy.
What you will find here
The library covers five areas — Business & Trade, Finance, Lifestyle, Legal, and Agriculture — currently 300+ calculators, each paired where it helps with a written guide that works the same problem by hand, step by step, so the number can be checked independently of the tool.
An honest boundary
Alex is not a licensed financial, tax, legal, or medical professional, and no guide on this site should be treated as professional advice. The tools and articles explain public formulas and official documents for reference. For decisions with real consequences — a contract, a tax filing, a medical question — use the calculation here as a sanity check, then verify with the relevant official source or a qualified professional. The disclaimer spells this out in detail.
Contact
Questions, corrections, and partnership inquiries: [email protected].
Last updated: September 13, 2026.