Evaluating Intelligence

Evaluating Intelligence — universally called Eval Int — is the Magery damage-scaling skill. It's what Tactics is to weapons: a flat multiplier on every direct-damage spell the mage casts. The skill also reads target mana for tactical information, scales buff and debuff spell magnitudes, and substitutes for Wrestling defense when paired with Anatomy. No serious mage skips Eval Int — without it, Magery deals base damage with no multiplier.

Spell-damage scaling

The defining function of Eval Int is its damage multiplier on direct-damage Magery spells. The factor scales linearly from 1.0× at 0 skill to 4.6× at 120 skill:

direct_dmg_total = base_damage × (3 × Eval Int / 100 + 1)

Each 33-point increment roughly adds 1.0× to the multiplier. The ceiling is 4.6× at 120 — the only way to push damage higher is Spell Damage Increase items (capped at 15% PvP / 100% PvM in modern UO) and Inscription (the inscription-bonus formula adds 10% spell damage at GM).

The multiplier applies to every Magery direct-damage spell: Magic Arrow, Harm, Fireball, Lightning, Energy Bolt, Explosion, Flamestrike, and the seventh-circle direct-damage line. It does not apply to Summons, Resurrection, Mind Blast, or Poison.

Buff and debuff scaling

Eval Int also scales positive and negative stat-modifying spells:

Positive buffs (Bless, Strength, Agility, Cunning)

final_stat = base_stat × (1 + (1 + Eval Int / 10) / 100)

A 100 Eval Int caster casting Strength on a 110 STR target:

110 × (1 + (1 + 100/10) / 100) = 110 × 1.11 = 122 STR

Negative buffs (Curse, Weaken, Feeblemind, Clumsy)

final_stat = base_stat × (1 - (8 + (caster_eval_int - target_resist) / 10) / 100)

A 100 Eval Int caster casting Weaken on a target with 50 Resist and 100 STR:

100 × (1 - (8 + (100 - 50)/10) / 100) = 100 × 0.87 = 87 STR

The differential between caster Eval Int and target Resisting Spells is what drives the magnitude of the debuff. A high Eval Int + low-Resist target produces the maximum debuff; a low Eval Int + high-Resist target produces the minimum.

These spells are resistible — see the Resisting Spells article for the contested-roll outcome on whether the spell lands at all. Once landed, Eval Int sets the magnitude.

Active use — reading target mana

Targeting another player or creature with Eval Int returns:

• The target's mana percentage remaining.
• An estimate of their overall Intelligence stat.

This is the mage's PvP tactical opener — read the target's mana to gauge how many spells they can still cast before going dry, and adjust the engagement accordingly. A 0-mana mage is harmless until they regen back; a 120-Int mage with full mana is a catastrophic threat.

The active read costs a skill check; below GM the read may fail and produce no information. At 100+ the read is reliable.

Defensive substitute (with Anatomy)

Eval Int paired with Anatomy can substitute for Wrestling or other melee skills for defensive contested rolls. The formula:

defense = (Eval Int + Anatomy + 20) / 2,  capped at 120

A 100 Eval Int + 100 Anatomy mage reads as 110 melee defense — equivalent to 110 Wrestling. Pushing both to 120 produces (120 + 120 + 20) / 2 = 130, which the cap clamps to 120.

This formula lets a mage drop Wrestling entirely and still defend against incoming melee — at the cost of 200 skill points (Eval Int + Anatomy) which would otherwise pay for Wrestling alone (100 points). The trade is freeing the mage's hand to hold a real Mage Weapon (Imbued/Reforged staff) instead of a defensive spellbook, plus the Eval Int spell-damage multiplier and the Anatomy passive bonuses.

Mysticism — historical link

Pre-Publish 64 (February 2010), Eval Int also scaled Mysticism spell damage the same way it scales Magery. Pub 64 changed Mysticism's secondary-skill scaling to either Imbuing or Focus instead. After the change, Eval Int has no effect on Mysticism damage. Old guides that suggest building Eval Int for Mysticism are pre-Pub-64 and incorrect for modern UO.

Training

A mage training Magery from 0 to 120 will typically have Eval Int in the 80-100 range when Magery hits cap — passive accumulation does most of the work. The Reactive-Armor spam closes the last 20 points.

Build context

• Pure Mage. 120 Magery + 120 Eval Int + 120 Resist + GM Med + 100 Inscription + 100 Wrestling. Eval Int is non-negotiable; the 4.6× damage multiplier is the build's primary damage source.
• Hybrid Caster (Necro-Mage, Mystic-Mage, Spellweaver-Mage). Eval Int boosts Magery only; the secondary school uses its own scaling (Spirit Speak for Necro, Imbuing/Focus for Mystic, none for Spellweaving). 100 Eval Int + 100 secondary-school-scaler is the conventional split.
• Tank Mage. GM Eval Int + GM Anatomy → 110 effective melee defense without Wrestling. The freed hand allows a Mage Weapon for melee mana leech.
• Stealth Mage. 100 Eval Int + 80 Hiding + 80 Stealth + 80 Wrestling — opens with a Magic-Arrow-from-stealth burst at 100 Eval Int's 4.0× multiplier. Niche but the only path to stealth-mage damage.

Strategy notes

• Don't skip Inscription. Eval Int's 4.6× multiplier doesn't compound with itself — Spell Damage Increase items and Inscription's GM bonus are the only ways to push above the Eval Int cap. A 120 Eval Int mage with 100 Inscription deals 110% damage of a 120 Eval Int mage without it.
• Active read is PvP utility. Open every duel with an Eval Int read on the opponent. Their mana state determines the engagement plan: low mana = press and force them dry; high mana = retreat and Med up before committing.
• Buff scaling is small. The buff formula contributes only ~10% extra at 100 Eval Int — the real prize is debuff scaling and direct-damage multiplication.
• Resist-vs-Eval differential. A high-Resist target neutralizes most of the Eval Int debuff bonus. Against a 120 Resist mage in PvP, Curse / Weaken hit at minimum effect. Direct damage (where Resist doesn't apply) is the path.
• Wrestling-mage with Eval Int + Anatomy + spellbook. A mage running Wrestling for defense plus Eval Int for damage and Anatomy for the mana-disrupt-on-hit benefit reads as a 110 defense AND a 100 wrestling mage — the redundancy is intentional and worth the points on a top-tier PvP build.

See also

Magery, Mysticism, Spellweaving, Necromancy, Anatomy, Wrestling, Resisting Spells, Meditation, Inscription, Spell Damage Increase, Lower Mana Cost, Mana Regeneration, Mage Weapon, Reactive Armor, Curse, Weaken, Bless, Strength, Twisted Weald, Satyr.