Software Windows

What does ‘open sourcing’ mean?

open sourcing
Calculated move: Microsoft is open sourcing its Calculator

You may have read this week that Microsoft is ‘open-sourcing’ the Windows Calculator. That’s fabulous, you doubtless said to yourself. What a lovely thing to do. Go Microsoft. But admit it, you haven’t got the first chuffing clue what they mean, do you? So here, in layman’s terms, is what open sourcing a piece of software actually means.

Open source software

Most commercial software is closed source. That means the general public has no access to the computer code that the software’s comprised of. A closed-source operating system such as Windows 10 will have millions of lines of computer code, but only Microsoft staff have access to them and have the legal right to amend the code.

The opposite of closed source software is – big reveal, drum roll – open source. With open-source software, the source code is freely published and anyone is free to inspect it, tinker with it or adapt it. Perhaps the most famous example of this is the Linux operating system. The Linux core is open source and then various organisations adapt it and distribute their own variations, such as Ubuntu, Red Hat and Fedora.

By and large, open-source software is free of charge, although companies may charge to support such software.

So why open source a calculator?

On the face of it, Calculator does seem a curious a little app to make open source. After all, how much can you do with a basic calculator?

However, as Microsoft explains on its blog, it’s not only throwing it open so that people can code or suggest improvements to Calculator itself, it’s offering up the code so that programmers can “easily integrate Calculator logic or UI into your own applications”.

Will this make a massive difference to the way the calculator operates in Windows? Who knows. But it can certainly do no harm to try. As Microsoft explains: “Calculator will continue to go through all usual testing, compliance, security, quality processes, and Insider flighting [testing], just as we do for our other applications.” 

So if you’ve ever fancied coding your own calculator, have at it!

Now read this: How can I create a plugin for WordPress?

About the author

Barry Collins

Barry has scribbled about tech for almost 20 years for The Sunday Times, PC Pro, WebUser, Which? and many others. He was once Deputy Editor of Mail Online and remains in therapy to this day. Email Barry at

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