WHIRLWIND EXPLANATION: Pokémon have a fixed, permanent score from 0 to 31 for each stat that affects how good that stat can ever get.

This calculator will figure out that score (called a "gene" or, more obtusely, an "IV") for you, so you can discard the unworthy. It's more accurate for higher-level Pokémon, so it's helpful to go into a level 100 wifi battle with someone and check your Pokémon's stats from there.

Stat calculator

Golduck
Golduck 		Base
stats		 Stats Effort Stats Effort Stats Effort Stats Effort Possible genes (IVs)
Level Level Level Level
HP 80
95–106
98–108
101–111
108–120
31
Attack 82
59–69
60–71
62–73
67–79
9
Defense 78
56–66
58–68
59–70
64–76
9
Special Attack 95
67–77
69–80
71–82
77–88
2
Special Defense 80
57–68
59–69
61–71
65–77
10
Speed 85
61–71
62–73
64–75
69–81
23

Congratulations, you've narrowed your Pokémon's stats down exactly!

This Golduck's Hidden Power inflicts Ground damage, with 66 power.

And for your copy/pasting pleasure:

31 HP; 9/9 Physical; 2/10 Special; 23 Speed

or start over