HI,
I have a decent size 2 bedroom house with a 100 amp panel. I want to put a sub panel in my garage that's about 50 feet away from my panel. I was wondering what the maximum sub-panel is that I can put in my garage. I have a small welder and a possible small compressor that I would like to put in there. If you could get back to me asap that would be great. Thank you...

This is a trick answer, there is no maximum size, your only limited to the max size branch breaker the panel could handle, which is probably 100 amp.

Calculate the total load of the equipment, increase that by 25%, and that will be your minimum size feeder to the subpanel.

I agree, and small compared to what? Numbers are better,voltage and amps,horsepower,BTU ,watts. And welders are different.