Each power, with the exception of First Aid, receives two additional ranks and follows the same algorithm as Powers from Mass Effect 2. As with Mass Effect 2's rank 4, Mass Effect 3's ranks 4-6 give two power choices with the sixth always being passive.
Depending on Shepard's level in a completed save you can have up to 51 points to carry over to ME3. However, imported saves of levels 26 - 30 will give two additional points per level totaling up to 61 points.
With one exception you can decide how your points are allocated before importing ME2 saves. For an easier explanation, let's assume you have a level 30 Shepard.
Any class ranks you had in ME2 will be given in ME3 (e.g. Rank 3 Warp).
You will start with 61 points between spent and unspent points (55 unspent + 6 spent in Rank 3 Warp).
Any points in a Loyal Power (e.g. Miranda's Slam) will be given back as unspent points.
If you wish to start ME3 with all 61 points unspent, import a save that has 51 unspent points or choose a different class than your ME2 import during character customization. You may also reset your points in the med bay once aboard the Normandy (this is useful if you use the same class in ME3 as your imported ME2 Shepard, but want to reallocate points).
Each player class has access to First Aid, a power that uses medi-gel to revive fallen squadmates and restore a portion of Shepard's health; Fitness, to increase health, shields and melee damage; a passive class power, to increase reputation and other class-specific bonuses; and 6 active powers.
The following is a list of powers available to each class. Powers available from the very beginning are marked with a ✓, while powers that need to be unlocked by leveling up are marked with a •.
Each player class is able to learn one additional bonus power. These are unlocked through conversations with your squad or through completion of DLC missions. Each squad member can unlock two bonus powers.