I'm amazed at how much different they can be. Here's my boy:
2 days - 1lbs, 8.6oz
1 week - 2lbs, 13oz
2 weeks - 4lbs, 3oz
3 weeks - 5lbs, 11oz
4 weeks - 7.5lbs
5 weeks - 12.3 lbs
6 weeks - 15.1 lbs
7 weeks - 18.4 lbs
8 weeks - 19.5 lbs
16 weeks - 39.2 lbs
1 year, 5 months - 134.1 lbs 30.5 inches (a big jump from the last time we'd been to the vet!)