Back in the days of 3e, you could make an off-hand attack any time you made a normal attack – but at a -5 penalty.
If you were lucky enough to be a ranger or monk or had the appropriate feat, you could reduce it to -2.
In 5e, it’s much simpler.
How Do I Make an Off-Hand Attack?
You can make a second attack with a light weapon you are holding in your other hand as a bonus action provided you have made a weapon attack with a light weapon as normal. Penalties apply in different circumstances.
When you make a normal attack with a light weapon, you can make an off-hand attack with another light weapon.
You do not add your ability modifier to the damage of that attack unless your modifier is negative.
To make an off-hand attack, you must be using light weapons (or be unarmed).
Here are all of the weapons that you can use to make an off-hand attack, provided you have another one of these weapons in your other hand for your main attack.
- Hand Crossbow
- Light Hammer
This gives you some interesting combinations, considering you can also throw a weapon with your off-hand, assuming it has the thrown property.
Also, make sure you are using finesse weapons if your dexterity is higher than your strength. That means use shortswords, scimitars, daggers, or the like.
If your Strength is higher, use light hammers, handaxes, or sickles.
Improving Off-Hand Attacks
The following feats and class abilities will improve your ability to fight two-handed.
Dual Wielder allows you to ignore the rule, which means you have to have two light weapons. If both weapons are one-handed weapons, it doesn’t matter if they have the light property or not.
In addition, you’ll gain a +1 to AC when wielding two weapons.
Two-Weapon Fighting is a fighting style available to Rangers, Fighters, and Paladins, or anyone with the Fighting Initiate feat.
The benefit here is that you will be able to add your ability modifier to the damage of your second attack, which is a step up from the original restriction.
Steps To Make the Best Two-Weapon Fighter:
1. Play a Ranger. Choose Favored Foe at 1st level for an additional 1d4.
2. Take the Two Weapon Fighting Style at second level to add a (usually) +3 to damage on the off-hand attack.
3. At 3rd level, take the Hunter subclass, and choose Colossus Slayer for an extra 1d8 damage per attack.
4. At 4th level, take the Magic Initiate (Druid) feat, and choose Shillelagh as one of your cantrips.
You can now wield two clubs that can each deal 2d8 + 1d4 + 3 damage. That’s a range of 4-23 damage for a single attack at 4th level.
Your second attack will be just the same, meaning that your total range of damage is 8-46.
At 5th level, you gain an extra attack. At 6th level, you should multiclass into monk to get flurry of blows, thus granting you five total attacks.