I used a small amount of meth smoked it how long before its out of my system ?

Depends: Could be from 5 to 10 days depending on your metabolism. On the other hand without sounding like a scold, doing meth and worrying about it is just as detrimental to your health & well being. It's not the "amount" of meth you used but the good probability of increasing use that it illegal and depending on your age very harmful

See below: Depending on the sensitivity of the method meth may be detectable in urine from 2-5 days after use.

Smoked Meth: will be out of your system in 10.7 hours, the same amount of time for intranasal intake with bioavailability of 67 %.