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

Clefairy
Clefairy 		Base
stats		 Stats Effort 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 Level
HP 70
31–34
34–37
36–39
38–42
41–45
43–47
46–50
48–53
50–56
58–64
70–77
27
Attack 45
13–15
14–17
14–18
15–19
16–20
17–21
18–23
19–24
20–25
23–29
27–35
18
Defense 48
13–16
14–17
15–18
16–20
17–21
18–22
19–24
20–25
21–26
24–30
29–36
8
Special Attack 60
15–18
17–20
18–21
19–23
20–24
21–26
23–27
24–29
25–30
29–35
35–42
22
Special Defense 65
16–19
18–21
19–22
20–24
21–25
23–27
24–29
25–30
27–32
31–37
37–45
12
Speed 35
11–14
12–15
12–16
13–17
14–18
14–19
15–20
16–21
16–22
19–25
22–30
4

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

This Clefairy's Hidden Power inflicts Fighting damage, with 42 power.

And for your copy/pasting pleasure:

27 HP; 18/8 Physical; 22/12 Special; 4 Speed

or start over