M19 Stats Calculator
Note that there is a big rework on stats scheduled for mod 20.
Also note that to get the effective results, you must also add in numbers which are not displayed on your character sheet, like Feat and Power bonuses, Boons, items Equip Powers, and Vorpal enchantment critical severity, on the Player Stats... It can be arduous to find all of them. I didn't check how rounding works ingame (because everything will change and that would be too much work now), so you may find small differences with ingame numbers, but it should still be pretty accurate if you input the proper numbers.
Average Damage : average damage (min - max) you'll deal, taking all of your stats and combat advantage uptime into account.
Regular Hit : average damage (min - max) you'll deal with a regular hit, without taking crit, deflect or combat advantage into account.
Average Heal : average heal (min - max) you'll do, taking all of your stats into account.
Regular Heal : average heal (min - max) you'll do with a regular heal, without taking crit into account.
While the average heal is important, for heal checks you have to consider the fact that you won't crit all of the time, and you can be unlucky, even with capped Critical Strike. So the most important thing to look at is your minimum heal. And that's the reason why more Power is better than capping Critical Strike, since we cannot spam our powers anymore to make the average heal matter more.
Potentially Lethal Damage
Effective HP : average amount of raw damage (pre-mitigated/pre-crit/CA) you can sustain. The higher the better, especially for tanks.
Potentially Lethal Damage : a regular attack that deals that much raw damage can potentially kill you (if it crits, and/or if you are surrounded if you inputted a non null enemy combat advantage uptime). Make sure that you can survive the mechanics of the dungeons you want to get in !