When you’re unsure about Fahrenheit vs Celsius, feet and metres, or just wondering how large a petabyte really is, there’s no substitute for a good conversion tool.

There are plenty of candidates online. Google has several (search “convert F to C” for an example). But if you just need something lightweight for your PC desktop, then Convert could prove very useful.

As you’d expect for something with a 152KB download, Convert is strictly no-frills. There’s no installation, no Help file, no extras of any kind: just unzip the single executable and run it when required.

Choose a measurement type, select your units and get converting

The interface looks a little overwhelming at first, with more than 20 tabs for its various conversion types (Acceleration, Amt of Substance, Angle, Area, Computer, Concentration, Density, Distance, Energy, Flow, Force, Light, Mass, Power, Pressure, Speed, Temperature, Time, Torque, Volume, Volume – Dry).

Fortunately, it’s all very easy to use. Just select the tab you need, and choose the appropriate input and output formats: “Week” to “Hour”, say. Type your starting value in the Input box, and the conversion is instantly displayed.

This all looks a little basic, but Convert does have some small but welcome bonuses. Like the ability to add multiple “Custom” conversions of your own, with a source unit name, a destination, and the conversion factor.

If you’ve no interest in converting “Flow” or “Force”, or you’re not exactly sure what “micromoles” are, then you’ll appreciate Convert’s ability to hide its more esoteric conversion tabs and reorder the rest.

And if you’d like to run Convert anywhere then the good news is it’s compatible with everything from Windows 95 upwards. Go take a look.