I have a Player that has a Dragonborn Rogue that on DnDBeyond it shows his Rapier, Shortbow, Longswords and some others showing +4 to Hit and +2 Damage. I can't find any logical reason why the to Hit and Damage has such high bonus on regular weapons. Does anybody know the answer? 

Thanks,

RJ

(new DM)

Your attacks add your proficiency bonus (+2 at level 1) and ability bonus (usually STR or DEX). The damage adds only the relevant ability bonus.

Mellie,

Thanks for you response and using these modifiers and bonus things still don't add up. Specific example. PC's  ability STR +1, Proficiency +2; Using Rapier it should have +3 to Attack and + 1 to Damage. However on DndBeyond it shows +4 to attack and +2 to damage. So I'm trying to figure out where the extra +1 on both sides is coming from. 

Here is a screen shot of this from DnDBeyond:

Rapiers are Finesse weapons. It could be using your DEX.

Quote from DM_rjbates >>

Mellie,

Thanks for you response and using these modifiers and bonus things still don't add up. Specific example. PC's  ability STR +1, Proficiency +2; Using Rapier it should have +3 to Attack and + 1 to Damage. However on DndBeyond it shows +4 to attack and +2 to damage. So I'm trying to figure out where the extra +1 on both sides is coming from. 

Here is a screen shot of this from DnDBeyond:

 what is the PC's Dex? Since the Rapier is finesse it uses either STR or DEX.

The above posters are correct. Looks like the player has a +2 Dexterity modifier.

Rapiers are finesse weapons, which use Strength or Dexterity. Using D&D Beyond, the sheet automatically assumes the higher value (which you would prefer to use) so it has selected your player's Dexterity. 

So all are totally right! The player does have a +2 Dex. I’m to new to this to know that finesse weapons can use the Dex modifier. Thanks so much! This has been bugging me and didn’t know where to look. 

Best Regards All