There is no such thing as a standard chain-sharpening file, as chain sizes vary from Chainsaw to Chainsaw and there is no standard answer as the file size really depends on the size of your chain. You need to check the gauge of your chain (see the article How do I sharpen a chainsaw?
However, if you look carefully at your chain, on the side, you will find some figures or numbers stamped into the metal of the links, which will tell you the size or pitch of your Chainsaw.
You should check with your chain manufacturer to be absolutely sure, but very roughly, pitch to chain file sizes tend to work as follows...
Engineer’s Tip – If you look at the top of your chain, on each cutting blade there should be a line marked. The angle of this is the angle to hold your file and will also tell you when to replace the chain because you can’t sharpen anymore
As ever, check with your manual or manufacturer if you are in any doubt.