Unit Converter

Convert length, weight, temperature, volume, area, speed and data — instantly, offline, with nothing tracked and no API calls, ever.

Seven categories, 40+ units, converted as you type with exact standard factors (1 inch = 25.4 mm, 1 lb = 453.59237 g). A swap button flips the direction; quick-conversion shortcuts handle the classics (km→mi, kg→lb, °F→°C). Pure JavaScript on the page: once loaded it works with the network off.

What it does

Most online converters are ad-farms wrapped around a server API — you send your query to them, they send back an answer wrapped in five ad slots and a cookie banner. This one computes everything locally. It also gets a detail wrong almost everywhere else: decimal vs binary data units. 1 GiB is 1073.74 MB, not 1024 MB, not 1000 MB — and this converter keeps Megabytes (decimal) and Mebibytes (binary) properly distinct.

Who it's for: developers converting between MB/MiB, cooks scaling US recipes, travellers doing km/miles and °C/°F in their browser, anyone who wants the answer without the ads.

What it explicitly does not do: it does not convert currencies (rates change daily and would require exactly the kind of online API this tool refuses to use), does not cover obscure specialist units (furlongs, bars, moles), and does not remember history between sessions. The download adds 40+ more categories, offline-cached currency rates, and a keyboard quick-convert bar.

Features

• Length, weight, temperature, volume (US kitchen units included), area, speed and data — 7 categories, 40+ units.
• Exact standard conversion factors, live as-you-type results, up to 10 significant digits with scientific notation for extremes.
• Swap button reverses any conversion in one click.
• Quick-conversion list per category, click to load that pair.
• Decimal/binary data distinction done correctly.
• Works fully offline once the page is loaded.

FAQ

Does the converter use an online API?
No — that's the point. Everything is computed by JavaScript on the page. Disconnect your network after loading and it keeps converting.

How precise are the conversions?
Factors use exact standards (25.4 mm to the inch, 453.59237 g to the pound). Results show up to 10 significant digits; very large or small values switch to scientific notation.

Why no currency conversion?
Currency rates change daily and would require a network call — the one thing this tool refuses to do. The paid download caches rates offline and refreshes them when you choose.

Can I use it commercially?
Yes — no attribution, no restriction.

Is there a subscription?
No. One-time purchase.