Promotions

Civilization 4 units earn experience points (XP) by winning battles and spend them on promotions such as Combat I to V (+10% Strength each), City Raider, City Garrison, Drill, Medic and Blitz. The first promotion comes at 2 XP, then 5, 10 and 17, attacking earns twice the XP of defending, and Barracks and other buildings give new units free experience.

Units in Civilization 4 gain experience points (XP) when they win battles and spend them on promotions: the first promotion comes at 2 XP, the second at 5, the third at 10 and the fourth at 17, per the Civilization 4 manual (p. 44), and there is no limit to how many a unit can take. Each promotion is a permanent bonus, such as +10% Strength from Combat I or +20% city attack from City Raider I, and which ones a unit can take depends on its category. Soren Johnson, the lead designer, writes in the manual's afterword (p. 183) that the system borrowed RPG leveling: "A swordsman with the City Raider promotion could become a city-killer."

3D close-up of several mounted knights with lances and red shields, an ox-drawn cart with red pennants driven by a robed figure, and two men with spears at left, on grassland by a river. — Gameplay on 2K's Beyond the Sword page: armored knights on horseback in red livery around an ox cart with a monk, with spearmen behind. Firaxis Games and 2K

Quick facts

XP for promotions	2, 5, 10, 17 and so on
Attacking	Twice the XP of defending
No XP	For defeating non-combat units; from animals past 5 XP; from barbarians past 10 XP
Free XP for new units	Barracks, Vassalage, Theocracy, Stable, Drydock, West Point, the Pentagon, a Great Military Instructor
Limit	None on the number of promotions
Promotions in the base manual	41
Great General promotions	Combat VI, Medic III, Tactics, Leadership, Morale (Warlords)
Beyond the Sword	Woodsman III; air promotions Interception, Range, Ace

Sources: Civilization 4 manual, pp. 43-45 and 136-145; Warlords manual, pp. 11, 33, 103-104; Beyond the Sword manual, pp. 23, 26.

Earning experience

A unit earns more XP for beating a stronger opponent than a weaker one, and twice as much for winning an attack as for winning a defense, the Civilization 4 manual (p. 44) explains. It earns nothing for capturing Settlers or Workers. Animals stop giving XP once a unit has 5, and barbarians once it has 10, so a unit cannot be leveled far on them.

When a unit has enough XP, the promotions it can take appear among its action buttons; one click picks a promotion, per the manual (p. 45). Charismatic leaders need 25% fewer XP for each promotion, per the Beyond the Sword manual (p. 11); see Leader Traits. In Warlords, a Great General's Leadership promotion adds +50% to the XP its unit earns in combat.

Free experience for new units

Source	Free XP	Note
Barracks	3	The Warlords manual (p. 104): patch 1.61 cut it from 4 to 3 and the cost from 60 to 50; the base manual's text says 2
Vassalage civic	2	All new units
Theocracy civic	2	Units built in cities with the State Religion
Stable	2	Mounted units (Warlords)
Drydock	4	Naval units; also builds ships 50% faster
Airport	3	Air units (Beyond the Sword)
Great Military Instructor	2	A Great General settled in the city (Warlords)
The Pentagon	2	World wonder; new units in all cities
West Point	4	National wonder; new units in its city
Red Cross	Medic I	National wonder; units built in its city start with the promotion

Sources: Civilization 4 manual, pp. 45, 123 and charts pp. 210-215; Warlords manual, pp. 11, 33, 104; Beyond the Sword manual, p. 45.

Barracks, Vassalage and Theocracy add up, the manual (p. 45) says, so a unit built in a city with all three starts with 6 or 7 XP (depending on the Barracks rule above), already enough for two promotions. Two leader traits hand out promotions instead: Aggressive gives melee and gunpowder units a free Combat I, and Protective gives archery and gunpowder units free City Garrison I and Drill I, per the Civilization 4 manual (p. 159) and the Beyond the Sword manual (p. 11). The Heroic Epic and West Point both need a unit of a certain level before they can be built; see National Wonders and Projects.

Every promotion

Promotion	Available to	Needs	Effect
Combat I to V	Recon, archery, mounted, melee, siege, gunpowder, armored, helicopter, naval	The level before	+10% Strength each; IV also heals 10% more per turn in neutral lands, V in enemy lands
Accuracy	Siege	Barrage I	+10% city bombard damage
Ambush	Siege, gunpowder, armored, helicopter	Combat II	+25% vs armored units
Amphibious	Recon, archery, mounted, melee, siege, gunpowder	Combat II	No penalty attacking from the sea or across a river
Barrage I	Siege, armored	none	+20% collateral damage
Barrage II	Armored	Barrage I	+30% collateral damage; +10% vs melee
Barrage III	Armored	Barrage II	+50% collateral damage; +10% vs gunpowder
Blitz	Mounted, armored, helicopter	Combat III	Can attack several times per turn
Charge	Mounted, melee, armored, helicopter	Combat II	+25% vs siege weapons
City Garrison I / II / III	Archery, gunpowder	The level before	+20% / +25% / +30% city defense; III also +10% vs melee
City Raider I / II / III	Melee, siege, armored	The level before	+20% / +25% / +30% city attack; III also +10% vs gunpowder
Commando	Recon, archery, mounted, melee, gunpowder, armored	Combat IV	Can use enemy roads
Cover	Melee, gunpowder	Combat I	+25% vs archery units
Drill I	Archery, siege, armored, helicopter, naval	none	+1 first strike chance
Drill II	Same	Drill I	1 extra first strike; 20% collateral damage protection (patch)
Drill III	Same	Drill II	+2 first strike chances; 20% more collateral damage protection (patch)
Drill IV	Same	Drill III	2 first strikes; +10% vs mounted; 20% more collateral damage protection (patch)
Flanking I	Mounted, armored, helicopter, naval	none	+10% withdrawal chance
Flanking II	Same	Flanking I	+20% withdrawal chance; immune to first strikes
Formation	Archery, mounted, melee, gunpowder	Combat II	+25% vs mounted units
Guerilla I / II	Recon, archery, gunpowder	The level before	+20% / +30% hills defense; II also double movement in hills
Guerilla III	Same	Guerilla II	+25% attacking into hills (added by patch)
March	Recon, archery, mounted, melee, siege, gunpowder	Medic I	Heals while moving
Medic I	Recon, archery, mounted, melee, siege, gunpowder, naval	Combat I	+10% healing per turn for units in the same tile
Medic II	Same	Medic I	+10% healing for units in the same and adjacent tiles
Mobility	Mounted, armored	Flanking II	Every terrain costs 1 move
Navigation I / II	Naval	The level before	+1 movement each
Pinch	Mounted, gunpowder, armored, helicopter	Combat I (and Gunpowder, by patch)	+25% vs gunpowder units
Sentry	Recon, mounted, helicopter, naval	Combat III	+1 visibility range
Shock	Archery, mounted, melee, siege	Combat I	+25% vs melee units
Woodsman I / II	Recon, melee, gunpowder	The level before	+20% / +30% jungle and forest defense; II also double movement there
Woodsman III	Same	Woodsman II	+2 first strikes; +50% attack in jungle and forest (Beyond the Sword)

Source: Civilization 4 manual, pp. 136-145, with the patch changes from the Warlords manual, pp. 103-104 and Woodsman III from the Beyond the Sword manual, p. 26. The Drill wording is the manual's own.

Since the patches in Warlords, City Garrison and City Raider also count when a unit defends or attacks a Fort, per the Warlords manual (p. 104).

Great General promotions (Warlords)

A unit led by a Great General can take five promotions no other unit can, per the Warlords manual (p. 11):

Promotion	Effect
Combat VI	+25% Strength
Medic III	+15% healing for units in the same and adjacent tiles
Tactics	+30% chance to withdraw from a losing battle
Leadership	+50% experience from combat
Morale	+1 movement

Source: Warlords manual, p. 11.

A Great General appears once your units have earned enough combat experience, tracked on the Military Advisor screen (F5). Attaching him to a unit as a Warlord splits 20 XP evenly among the military units in his tile, and the unit he leads also upgrades for free and keeps all its experience; he can instead settle in a city as a Great Military Instructor (+2 XP for its new units) or build a Military Academy (+25% military production), per the Warlords manual (pp. 10-11). Beyond the Sword raised the experience needed for each Great General, per its manual (p. 45). More on Great Generals is on Great People.

Air promotions (Beyond the Sword)

In Beyond the Sword, air units fight interceptors the way land units fight, and so earn experience and promotions of their own: Combat, Pinch and Ambush, plus three new ones, per the Beyond the Sword manual (p. 23). Interception raises the chance of intercepting enemy aircraft (SAM Infantry, Mobile SAM and Mechanized Infantry can take it too), Range extends a unit's range, and Ace raises its chance to evade. The manual gives no percentages for them.

Who can take what

The categories decide the roles. City Raider is open only to melee, siege and armored units, and City Garrison only to archery and gunpowder units, the Civilization 4 manual (pp. 138-139) shows; Barrage and Accuracy belong to siege (and, for Barrage, armored) units, and Navigation only to ships. Johnson's afterword (p. 183) gives two examples of one unit type made into different tools: a swordsman with City Raider becoming a "city-killer", and a pikeman with Medic that guards a stack against knights and also heals the wounded units in it. Combat explains how the bonuses enter a battle, and Units gives each unit's category.

Frequently asked questions

How much experience do you need for a promotion in Civ 4? A Civ 4 unit takes its first promotion at 2 XP, its second at 5, its third at 10 and its fourth at 17, per the Civilization 4 manual (p. 44); Charismatic leaders need 25% less.

What does City Raider do in Civ 4? City Raider I, II and III give melee, siege and armored units +20%, +25% and +30% Strength when attacking cities, and City Raider III adds +10% against gunpowder units, per the Civilization 4 manual (pp. 138-139).

What does the Combat promotion do in Civ 4? Each Combat promotion from I to V adds +10% Strength in Civilization 4, and Combat IV and V also speed healing in neutral and enemy lands, per the manual (pp. 139-140). A Great General's unit can add Combat VI for +25%.

What does Drill do in Civ 4? Drill gives Civ 4's archery, siege, armored, helicopter and naval units extra first strikes, Drill IV adds +10% against mounted units, and since the Warlords-era patches Drill II, III and IV each give 20% protection from collateral damage, per the Warlords manual (p. 103).

What does Medic do in Civ 4? Medic I heals units in the same tile 10% more per turn in Civilization 4, Medic II extends that to adjacent tiles, and Warlords' Medic III gives +15%, per the Civilization 4 manual (p. 143) and the Warlords manual (p. 11).

How much experience do Barracks give in Civ 4? Barracks give new units 3 XP after patch 1.61 (4 before it), per the Warlords manual (p. 104); the base Civilization 4 manual's text says 2.

Is there a limit to promotions in Civ 4? No: the Civilization 4 manual (p. 44) says there is no limit to the number of promotions a unit can receive.