CafeTran

Personally, I find the free GlosaryConverter the most useful tool for Studio :). Note that Studio must be installed for this tool.

In case you need an alternative, (I got a null pointer error exception with the Van Nellen tool this morning), there is also this Windows tool.
You need Windows or a Windows VM.
I found the output better than Van Nellen (easier to clean up for use as a CT glossary). (Though that could have been down to the glossary itself, rathet than the tool - I haven't compared the output directly.)

 

If you don't have Studio, you can use this free Java tool (which has been recommended in another thread) at least for converting sdltb Studio termbases.

 

Thanks for reminding. In a perfect world, CafeTran would handle these termbases itself. Van Nellen shows that it's possible :).