About Toolnest

Toolnest is a growing catalogue of free online calculators and utilities built and maintained by Golam Rabbani. Every tool runs entirely in your browser — no account, no tracking, no data ever leaves your device.

How we build a tool

1. Identify a real, repeated calculation people search for.
2. Trace the formula back to its primary source (ISO standard, medical guideline, academic paper, or official documentation).
3. Implement the calculation client-side in TypeScript with strict types — no server round-trips, no third-party APIs.
4. Verify the output against published worked examples and edge cases.
5. For YMYL topics (health, finance), we build from published government, clinical, and financial standards and include a disclaimer to consult a qualified professional.
6. Run a post-deploy audit: cross-check results against at least two independent reference calculators.
7. Publish the source formula and any assumptions inline on the tool page.

What you will not find here

• No fake ratings or manufactured reviews. Every result shown is computed live from your input.
• No AI-as-expert. We use AI for drafting copy; a human engineer verifies every formula against its primary source before it goes live.
• No ads above the fold. Ad slots appear below the tool output so they never compete with the answer you came for.
• No dark patterns. No pre-checked newsletter boxes, no exit-intent popups, no countdown timers.

Contact

Found an error in a formula? Have a tool suggestion? [email protected]. We aim to reply within two business days.