yes, usually it's from LMP. Depending on which website/book you are using, they should specify somewhere what they are using. Babycenter.com definitely does it that way. But I noticed my Dr. Sears book does 'fetal age' which is LMP-2 weeks, assuming 28 day cycles - it's approximately weeks since conception. Also, some places like babycenter.com will put you as however many weeks you have completed. so if you are IN week 8 it will say 'you are 7 weeks pregnant.' But other books that describe pregnancies week by week actually talk about what's happening during the week in question. Have I sufficiently added to the confusion??