Time Length

1 round during combat goes for 20 seconds in game.
Generally, the number of actions you can do in a round of combat will also be limited by the passing of time (~20 seconds in-game). This means all actions in a turn (including bonus actions and movements) should conceivably be possible to do within 20 seconds. This rule is meant to be interpreted softly and used more as a guide than a strict limit; enforcement of the rule is at the DM's discretion.
Any rules or effects which specify a duration of 1 minute will last for 3 rounds during combat.