In D&D, DC stands for Difficulty Class. It is a numerical threshold that a player must meet or exceed on a d20 roll to succeed at an action or resist a spell or effect. The DC determines how hard something is to do, such as climbing a rope, evading a breath weapon, or swinging an ax. When you roll an ability check or a saving throw of any kind, you have to roll equal or above the DC. The more difficult a check is, the higher its DC will be. The DC is set by the DM based on the complexity or danger of the task or effect. Some DCs are already set by certain monster or character stats, while others are made by the DM at the table. The typical difficulty classes are as follows:

• Very easy: 5
• Easy: 10
• Medium: 15
• Hard: 20
• Very hard: 25
• Nearly impossible: 30

For example, if you are making a Strength (Athletics) check to climb a wall and an ally gives you a leg up, the DM might lower the DC from 15 to 10. Many spells require saving throws and ability checks to negate but don’t even tell you what the DC is. That’s because the DC equals 8 + Your Spellcasting Modifier + Your Proficiency Bonus.