1234Tools

1,169+ free calculators and converters — finance, mathematics, engineering, health and everyday work. Static HTML/CSS/JS, no build step, no framework. Every tool runs entirely client-side: nothing typed into a tool is ever sent to a server.

Live at https://www.1234tools.com (GitHub Pages, main branch, root).

Built and maintained by MVR IT Services LTD.

Structure

URL	File
/	index.html — all tools, browsable by category
/<category>/	<category>/index.html, e.g. /finance/
/<category>/<tool>.html	an individual calculator/converter
/about/ /contact/ /privacy/ /terms/ /cookies/	site pages
any bad URL	404.html

Shared assets live in assets/ (CSS design system, JS behaviour, SVG icon sprite, logo, PWA icons). Calculator logic lives in engine/*.js, one file per tool.

PWA / offline

• manifest.webmanifest — installable app manifest.
• sw.js — service worker: precaches the shell, caches tool pages as visited (network-first), so tools keep working offline once opened. Bump the V version string in sw.js on every deploy so returning visitors' caches refresh.

Contact form

contact/index.html posts to FormSubmit.co (free, no account) → [email protected]. The first submission triggers a one-time confirmation email — click the link in it once and all future submissions deliver normally. Swap the address in the form's action attribute if you set up a dedicated inbox for the domain.

Design system

Dark-first theme (light/system also available), gold gradient accents, Sora (headings) + Inter (body) via Google Fonts. All colours are CSS variables in assets/app.css :root. Every tool page shares the same header, category sidebar and footer.

Deploying

Push to main — GitHub Pages publishes automatically. Domain: CNAME file (www.1234tools.com) + registrar DNS pointing at GitHub Pages; HTTPS enforced once GitHub issues the certificate.

Legal pages

Privacy Policy, Terms of Service and Cookie Policy are solid boilerplate for a client-side, no-account tool site — have a solicitor review before relying on them for anything contentious.