Safe, free and unlimited xls to xlsx converter?

[Mayhem]

I am in the situation that I need to convert a large number of xls sheets to xlsx to be compatible with my version of Excel. It is an institution license so I cannot convert manually due to the security restrictions imposed on the license by my institution.

I know there is a slew of online converters. These work PERFECTLY, except nearly all (if not all) require premium subscriptions for unlimited conversions. Does anyone know of a free and safe piece of software that performs this task automatically? I'd prefer if you have personal experience with it, as it's hard to know what can be trusted.

Thanks!

 

[pbuk]

I don't understand: xlsx is a newer format than xls so any version of Excel that can read xlsx files can also read xls.

 

[pbuk]

I don't understand: xlsx is a newer format than xls so any version of Excel that can read xlsx files can also read xls.

Or do you mean that the institution's installation of Excel (presumably on a machine controlled by the institution on which you do not have administrator access) prevents you from opening .xls files?

In this case I think you will need to do the conversion on another machine. You can get a 1 month trial of Office 365 for free.

Alternatively fork out the c.USD10 for 500 conversions at e.g. CloudConvert.

 

[berkeman]

It is an institution license so I cannot convert manually due to the security restrictions imposed on the license by my institution.

It sounds to me like you need to talk to your IT department about your question. If they have restrictions on the conversion for security reasons, they likely will not want you using some random tool to do the conversions.

 

[Vanadium 50]

I agree - talk to your IT department and see what they can do for you. I had the same initial reaction as @pbuk - why can't you read in the old version and write the new version, Script it if you need to.

The XLSX format is not difficult to understand: it's a set of XML files, ZIPped together. Writing your own converter is an afternoon's work (debugging it may take longer) and the hardest part is probably finding the 20-year old XLS documentation. If you could do this on unix, you have a bunch of tools already there: your job then becomes to stitch them together.

 

[jedishrfu]

Also using some free tool might mean your sheets could be exfiltrated to some external site ie compromise the privacy and security of your data.

 

[Mayhem]

I agree - talk to your IT department and see what they can do for you. I had the same initial reaction as @pbuk - why can't you read in the old version and write the new version, Script it if you need to.

The XLSX format is not difficult to understand: it's a set of XML files, ZIPped together. Writing your own converter is an afternoon's work (debugging it may take longer) and the hardest part is probably finding the 20-year old XLS documentation. If you could do this on unix, you have a bunch of tools already there: your job then becomes to stitch them together.

I unfortunately have graphical data embedded in the Excel files (this is HPLC chromatography data), so maybe it is not as easy. But I would not know.

 

[Vanadium 50]

I don't think graphics are a problem. Why would it be any worse than formulas?

 

[Ibix]

As others have noted, Excel should be able to do this - so the problem is the institutional settings.

Are you (or is your boss) sufficiently senior to make this your IT department's problem to solve?

If not, how secret/sensitive is your data? Would sticking the files on a USB key and taking them to an external laptop violate any company policies and/or laws? Use a different Excel install. LibreOffice can open xls and write xlsx if you don't want to shell out for an MS Office license.