Dark Souls II stat softcaps

Vigor (health added per point)
1-19 = 30
20-49 = 20
50 and up = 5

Endurance (stamina added per point)
1-19 = 2
20 and up = 1

Vitality (equip load added per point)
1-29 = 1.5
30-49 = 1.0
50-69 = 0.5
70-97 = 0.5 per two points of Vitality
98 = 0.5

Attunement (total spell slots)
1-9 = 0
10-12 = 1
13-15 = 2
16-19 = 3
20-24 = 4
25-29 = 5
30-39 = 6
40-49 = 7
50-59 = 8
60-74 = 9
75-99 = 10

Strength (total Strength attack bonus)
1 = 50
10 = 57
20 = 80
30 = 102
40 = 140
50 = 155
60 = 162
70 = 170
80 = 185
90 = 192
99 = 200

Dexterity (total Dexterity attack bonus)
same as Strength chart

Intelligence (total magic bonus)
same as Strength chart

Faith (total Lightning bonus)
same as Strength chart

Adaptability has no chart, but raising Adaptability and Endurance creates natural poise by raising both stats at the same rate. Your poise only gets as high as your current Adaptability stat. Raising the lower of the two stats will result in a Poise increase.