Blog - Sébastien Mouchet

A small tool for time zone conversion

Posted on March 31, 2024, by Sébastien

International Meeting Planner

I’m writing this short blog post to let you know about a small (unassuming) tool I've just written, to help you visualize suitable times for events involving multiple time zones.

“International Meeting Planner” screenshot
“International Meeting Planner” screenshot

You can download it at:

It was loosely inspired by tools such as World Time Buddy:

Except, it’s more basic, and a lot uglier.
If it looks like a UI designed by a backend developer, that’s because it is 😁

What’s the point, then?

There are multiple advantages:

Just save the HTML file to your computer and open it in a Web browser.


Say what?

OFFLFIRSOCH. It’s apparently pronounced “awful fur sock”.
It’s an idea from Solderpunk – the creator of the Gemini protocol – and it means “OFFLine-FIRst SOftware CHallenge”.

The spirit of OFFLFIRSOCH, in short, is […] to identify something which you yourself actually do online at least semi-regularly which you know full well could be done offline, and to make that happen.

That’s how I got the idea of developing this small utility.

Indeed, why send requests to a server when time zone conversions can be done entirely locally on your computer?

I found out about this “challenge” on March 29, and it ends on March 31 😅

Now, to be honest, I doubt my tool qualifies for the challenge, as it’s… a Web page! So much for “offline FIRST”.
I mean, it can definitely work 100% offline, but if anyone ever finds it useful, they’ll be tempted to host it on a server, which defeats the purpose of the entire thing.