due dates

I'm wondering, when calculating your edd do you go by your last period, LMP
Or date of conception?

I've got different dates on different due date calculators.....

LMP nov 7th

I will go for an early scan, I've heard 8-9 weeks is best for dating.... Is that right ?

Help me figure out my edd please ?

i was told with this pg and my last one, that at 6 weeks they can give you the date as the heart beat is visable then. but id rng and ask once you have a referal as every place has diffrent opinions on it.

I got my dating scan (I knew my dates but wanted to see bub) at 6w5d. There was a visable heartbeat and bubs was measuring on my dates. Everyone will want to go with LMP, and seeing as I don't have a 28 day cycle and o'ed on cd 17, I just changed my LMP date to match my dates, which were calculated from conception, and with both the scans I've had have proven to be correct, spot on. So it's up to you, really.

Well my dates range from August 14 to August 18 off four different websites, guess I'll wait for the ultrasound... I gave birth at 38 weeks before so it's not a real date anyway ;)