How do you check what gauge strings you are using?

[BegBass]

Since I bought my bass used, I have no idea what strings I have. How can I check the gauge? Or should I buy new strings and experiment?

[BryanM]

You could try using a caliper but I don't know how exact a result it would get you. Personally I'd recommend experimenting.

[speedkills]

Since you got the bass used a new set of strings is probably in order anyway...

[DavePlaysBass]

Calipers will get you close. You may need to make a few measurments because there will be variation due to the coaresness of the wrap.