Converter NOW: Convert Anything as You Type

There is a special kind of despair reserved for unit converters on the web. You search "5 miles in km", and the first result is a page last redesigned in 2009, buried under ads, cheerfully asking for your location "to improve your experience". It is a unit converter. It needs my location the way a toaster needs a wifi password.

So when I stumbled on Converter NOW on GitHub, a free and open-source converter built by Damiano Ferrari, promising speed, no ads and no data collection, I paid attention.

Quick honesty note, as usual here: this article is based on the official site, the GitHub repository and the store listings. I have not run a full hands-on test on my own machine yet, so everything below comes straight from those sources.

What Converter NOW is

Converter NOW is a unit and currency converter that runs on Android, Windows, Linux and in the browser. The project started in 2018, when the developer got fed up with converters that were, in his own words, ugly, complex and full of ads, and decided to build his own. It is now on its fourth major version, translated into 14 languages, and licensed under GPL-3.0.

The idea is disarmingly simple: you start typing a number, and every other unit on the page updates in real time. No "Convert" button, no dropdown maze, no page reload. One field, everything else follows.

The catalogue covers more than 200 units across the classics (length, area, volume, mass, time, temperature, speed, pressure, energy, power) and some delightful oddities: numeral systems for the programmers, fuel consumption for the road trippers, SI prefixes for the students, and shoe sizes for anyone who has ever tried to buy sneakers on a foreign website. That last one alone earns it a bookmark.

The details that won me over

A few things stand out beyond the basics.

You can reorder and hide units. If your life is kilometers and miles, drag them to the top and banish the poundals to the shadow realm. Your layout is yours, and a recent update added import and export, so your setup survives a change of device.

There is a calculator built into every page, which sounds minor until you need "half of 3.5 liters, converted to cups" while cooking with an American recipe and a European kitchen.

Currencies are there too, about thirty of them, with exchange rates updated daily. And the privacy posture is exactly what this blog likes to see: no ads, no trackers, no data collection, and the only permission the app asks for is internet access, solely to fetch those currency rates.

Where to get it

This is where Converter NOW is unusually generous. On Android, you can grab it from the Play Store, F-Droid, or as an APK from GitHub. On Windows, it is in the Microsoft Store and one winget command away. On Linux, take your pick: Flatpak, AppImage, Snap, or a plain archive. And if you want to install nothing at all, the web app at https://converter-now.web.app does the job from any browser. Feeling fancy? The web app is even self-hostable with a single Docker command, for those of us who enjoy hosting a unit converter at 2 a.m. for no practical reason. No judgment. Some judgment.

The honest limits

A few caveats before you rush in. The currency list is limited to about thirty currencies, because the app relies on the free rates published by the European Central Bank. If you need an exotic currency, you may not find it. There is no iOS app, so iPhone and Mac users will have to live with the web version. And it stays in its lane: it is a converter, not a scientific toolbox, so do not expect date calculators or equation solvers.

Verdict

Converter NOW is the kind of tool this site exists for: a small, focused program that does one thing well, respects you, and asks for nothing. It is free, open source, available on basically everything with a screen, and it replaces a whole category of sketchy ad-riddled websites in one move. If you convert units even occasionally, bookmark the web app now and thank yourself later.

Official links: try the web app at https://converter-now.web.app right in your browser, or grab the code from the GitHub repository at https://github.com/ferraridamiano/ConverterNOW and build it yourself.