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

Horsea
Horsea 		Base
stats		 Stats Effort Stats Effort Stats Effort Stats Effort Stats Effort Stats Effort Stats Effort Stats Effort Stats Effort Stats Effort Possible genes (IVs)
Level Level Level Level Level Level Level Level Level Level
HP 30
29–32
30–34
32–36
34–38
35–40
37–42
38–44
40–46
46–53
50–57
12
Attack 40
14–18
15–19
16–20
17–21
17–22
18–23
19–24
20–26
23–30
25–32
31
Defense 70
21–25
23–27
24–28
26–30
27–32
28–34
30–35
31–37
37–44
40–47
27
Special Attack 70
21–25
23–27
24–28
26–30
27–32
28–34
30–35
31–37
37–44
40–47
12
Special Defense 25
11–14
11–15
12–16
12–17
13–17
13–18
14–19
14–20
16–23
17–25
10
Speed 60
19–23
20–24
21–26
23–27
24–29
25–30
26–32
27–33
32–39
35–42
9

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

This Horsea's Hidden Power inflicts Ground damage, with 54 power.

And for your copy/pasting pleasure:

12 HP; 31/27 Physical; 12/10 Special; 9 Speed

or start over