I always measure a sweater that I like the fit of and use those measurements. Usually a pattern gives you the finished measurements of the sweater in addition to your measurements. You need to have a certain amount of ease in a sweater so it's not skin tight.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry