A naked level 60 character should have 4721 HP, and the calculator shows 1546.
The formula should be:
Where Life% is the sum of all your items that give +% to Life, clvl is the character's level, and VIT is the character's vitality.
Looks like you guys don't have the additional life you get from vitality as you level. Above level 35, you get one additional life per point of vitality. That's what the max(10,clvl-25) is doing in the formula above.