Gauge swatch newbie question

I’ve only made one other full knitted pattern (I’m a crocheter), and it was for my son; he didn’t care if it turned out too big…which it did, so I wasn’t worried about gauge.
I’m starting the mommy snug from the Interweave summer edition and am making a proper gauge swatch. I usually (with crochet), just do the swatch then unravel it, but I want to keep this for referral later.
My question is pretty basic. Do I count the cast off row as the 30th row, or do I knit up 30 full rows, then cast off?
Thanks a million

I’d knit at least 34-36 rows, so that the cast-on and bind-off didn’t influence my row count/measurement.

Swatches should be measured across stitches, and not across cast-ons, bind-offs and edges. Knit a swatch about 5 x 5 and the measure the 4 inches in the center.

Here is a good article on swatching.

Thanks a million. The knitty article was fantastic. I’ll frog what I have and start over with those suggestions. I may even go the trouble of washing and drying it; that’ll let me know if it’s going to shrink in the width or height too.