Originally Posted by merlinextraligh

this calculator allows you to layout graphically how various gear combinations work.

http://www.gear-calculator.com/#

As pointed out above a 50/11 is actually a bigger gear than a 53/12. Thus by swapping out your cassette you can get pretty much the same gearing with the compact, as with a standard crank.

There will be differences here and there, in what point you cross over from the little to the big ring, and there will be diffferences in the gaps between various gears.

Depending on your terrain, how fast you usually cruise, and your desired cadence, you may prefer one setup over another because the spacing of the setup fits you better.

That said, your gearing is not affecting your ability to keep up with the group, with the only exception being if the lowest gear on the standard crank is requiring you to pedal too high of cadence on climbs, and the compact with a lower gear allows you to spin more efficiently.