Does the Fencing Master feat stack with the 5th level extra attack?

Question

Do the extra attacks from the Fencing Master feat and the extra attack 5th level class benefit stack? Do I get to attack 3 times in one turn when having both of these?

Answer 1

Yes, you get can get 3 attacks, but with a -5 penalty to each. Rarely worth it.

Once on your turn when you use your action to make a melee attack with a finesse weapon, you can make one additional attack with that weapon, but all of the attacks that are part of the action take a –5 penalty to the attack roll.

At 5. level as a paladin you can make melee 2 attacks as an action. With this feat (wielding the right weapon), you can decide to make one additional attack, but in this case you take a -5 penalty to all three attacks. Doing so is rarely good for you, usually only worths it if you have advantage.*

The main attraction of Fencing Master from an optimization standpoint is the ability to parry the attack with a reaction.

Connecting to your other question regarding an empty hand, even with this feat you benefit from a shield in your other hand.

*The mathematics of when is it better to attack 3 times with -5:

2 * H * D < 3 * (H-0.25) * D
2 * H < 3 * H - 0.75
2 * H + 0.75 < 3 * H
0.75 < H

Where H is your hit chance, and D is your damage. The 0.25 is the -5 converted from roll penalty to hit chance. As you can see, if you have a 0.75 chance (in other words you hit on a 6) it makes sense to make 3 attacks.