5.5e / 2024 · 5e / 2014 · Pathfinder 1E · D&D 3.5e

Armour or Shield of Fortification

Fortification magic protects a wearer from the most dangerous part of a critical strike. Pathfinder 1E and D&D 3.5e use the named Fortification property with light, moderate and heavy grades. The two 5e rulesets do not use that subsystem.

Rules: choose the edition tab below. The Fortification percentages are not interchangeable between Pathfinder 1E and D&D 3.5e.

Explore: Magic Armour & Shields · Adamantine · Combat

At a Glance

Property	Fortification
Purpose	Reduces the danger of critical hits and, in 3.x, sneak-attack extra damage
5e analogue	Adamantine Armor turns Critical Hits into normal hits
Pathfinder 1E	Light 25% · Moderate 50% · Heavy 75%
D&D 3.5e	Light 25% · Moderate 75% · Heavy 100%

D&D 5.5e / 2024
D&D 5e / 2014
Pathfinder 1e
D&D 3.5e

5.5e / 2024

There is no core Fortification property with light, moderate and heavy grades. Do not use the Pathfinder/3.5 25%, 75% or 100% negation chances in a 2024 game.

The closest core SRD analogue is Adamantine Armor: while the character wears qualifying adamantine armour, a Critical Hit against that character becomes a normal hit. It is an uncommon magic item and does not use the 3.x enhancement-equivalent system.

A 2024 shield that protects against critical hits would therefore be a specific custom magic item unless an official item supplies its own rule.

5e / 2014

There is no core Fortification property with light, moderate and heavy grades. The 2014 core equivalent is likewise Adamantine Armor: while worn, a critical hit against the wearer becomes a normal hit.

Do not import the 3.x percentage roll, +1/+3/+5 bonus-equivalent pricing, caster level or Craft Magic Arms and Armor requirement into a 2014 game.

Pathfinder 1E

Fortification produces magical protection around vital areas. When a critical hit or sneak attack would apply, roll the fortification chance. On a success, the attack still hits and deals normal damage, but the critical-hit or sneak-attack extra damage is negated as the Pathfinder 1E property specifies.

Grade	Chance for normal damage	Price modifier
Light	25%	+1 bonus
Moderate	50%	+3 bonus
Heavy	75%	+5 bonus

Aura: strong abjuration · CL: 13th · Construction: Craft Magic Arms and Armor, limited wish or miracle.

Pathfinder deliberately uses lower moderate and heavy chances than D&D 3.5e. Keep the Pathfinder 25/50/75 progression separate from the 3.5e 25/75/100 progression.

D&D 3.5e

D&D 3.5e uses the same three Fortification grades and the same broad purpose: a percentage chance to negate the extra damage from a critical hit or sneak attack while leaving the underlying hit intact.

Grade	Negation chance	Price modifier
Light	25%	+1 bonus
Moderate	75%	+3 bonus
Heavy	100%	+5 bonus

Aura: strong abjuration · CL: 13th · Construction: Craft Magic Arms and Armor, limited wish or miracle.

Resolve the attack using 3.5e critical-hit, sneak-attack and item-creation rules rather than Pathfinder revisions.

Why Fortification Matters

Fortification is protection against damage spikes rather than ordinary hits. A character can still be struck; the property matters when the attack would otherwise multiply damage or add precision damage.

The most important table rule is edition discipline: Pathfinder 1E deliberately changed the moderate and heavy percentages from D&D 3.5e.

Run It Correctly

Choose the campaign edition before resolving the hit.
In 5.5e/2024 or 5e/2014, use the actual magic item’s text; core Adamantine Armor converts the Critical Hit to a normal hit.
In Pathfinder 1E or D&D 3.5e, roll the appropriate Fortification percentage when the property applies.
Do not use the 3.x +1/+3/+5 pricing or percentage table in either 5e ruleset.