Software always needs to balance performance and features. This page collects options to tweak that balance. Be aware that whenever you improve performance, you lose features, there is no free lunch. And don't expect miracles, usually you gain only 5-15% speed. The special modes to read and write Excel are an exception, they can save a lot of time. But even small gains may be worth it, if you frequently process huge files.



  • Try to support Libre Office: if you don't use Libre/Open Office (only needed for ods files), switch this off to save a few seconds loading time
  • Try to support MultiTerm: if you don't want to create sdltb files, switch this off to save a few seconds loading time
  • Silent Mode: You can shave off a few percentage points by disabling progress bar updates.
  • Redundant Fields: Sometime data can contain contain unnecessary duplicate fields. This can happen after merging, or manual changes by users. Examples are multiple fields with the same content (source: Wiki, source Wiki), or multiple picklists of the same type (color[red, green], color[blue, green]). Generally, it's better to clean those up by merging (source: Wiki, color[red, blue, green]). If you prefer speed gains over such cleaning, switch it off.
  • Fast Mode: Opening large and complex spreadsheets can take quite long. Much of that time is spent verifying if rows, columns, or pages are hidden, and resolving formulas. In most cases, though, users don't hide data and don't use macros and formulas in term lists. So by default, this setting is active. It is a big time saver, more than twice as fast. Disable if you need to use more complex Excel features. This is also the mode to choose when you run into memory errors when converting huge spreadsheets.
  • Large file mode: Writing very large Excel files can result in an out of memory error. In that case, try using this large file mode. It's also significantly faster, up to 50%. It is recommended to always use this option. 
    Due to some last minute changes, it does not skip any formatting, contrary to what the UI says.
    It will probably disappear as an option and become the standard. Until it has been tested more thoroughly, you can still switch back to legacy mode by disabling it.
  • Do not format Excel: The converter applies formatting to Excel, to make it more readable. If you are OK with plain data, disable this box and you gain a few percent of performance.
  • Verify and fix XML files: Some XML files out there are slightly wrong. They may contain invalid character references, or broken Unicode. The converter can fix some of these problems. It's usually best to activate the option, but it takes a little bit of time. So if you convert very large xml files, and know they are valid, disable it.


The speed bar at the bottom gives you an idea how much performance you may gain, as you toggle features. This is just a rough guide; the exact number depends on an almost infinite number of factors. 


Another way of visualising the difference is below. Each chart starts with the fastest conversion: that's when all settings are tuned to optimise speed, at the expense of features. The other segments indicate how much time you add when optimising for features. As you can see, some options have little influence, while others can save quite a bit. The samples were measured when converting a German-English 150.000 entry extract from IATE


Xlsx > Tbx        



Tbx > Xlsx

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