Armor Class Guide
Understanding Armor Class
Armor Class is the target number an attacker must meet. A higher value makes hits less likely. This calculator helps you check that number before play. It follows common fifth edition patterns. It also lets you add table specific bonuses.
Why AC Changes
AC can change during a fight. Armor gives a base value. Dexterity may add to it. Medium armor limits that Dexterity gain. Heavy armor normally ignores Dexterity. Shields add a steady bonus when equipped. Cover can raise AC against some attacks. Spells and class features can raise it for a short time.
Using the Tool at the Table
Pick the method that matches your character. Choose the armor item or enter a custom base. Add ability scores, not modifiers. The tool converts each score for you. Select a shield when one is held. Add magic item bonuses only when they apply. Then include cover, spells, and feature bonuses. The result shows each part of the total.
Rules Notes
Unarmored Defense is special. A barbarian uses Dexterity and Constitution. A monk uses Dexterity and Wisdom. A monk loses that feature while using a shield. Mage Armor uses a base of thirteen plus Dexterity. Natural armor often uses thirteen plus Dexterity. Some races or monsters use fixed bases. A Tortle style base is seventeen and ignores Dexterity.
Practical Advice
Treat temporary bonuses carefully. The Shield spell adds five only for its duration. Haste adds two while the spell lasts. Cover applies only from the right angle. A shield bonus needs a free hand and an equipped shield. Magic armor and magic shields stack because they improve different items. Many protection items also stack unless a rule says otherwise.
Checking Builds
Use the example table to compare armor choices. A rogue may prefer studded leather and high Dexterity. A cleric may prefer medium armor and a shield. A fighter may use plate, a shield, and Defense style. The best AC depends on cost, stealth, strength, and story. Always confirm final rulings with your Dungeon Master. For monsters, enter the printed base and choose no Dexterity when needed. This keeps homebrew creatures simple. Store exports after level ups, loot changes, and major spell choices between long campaign sessions.