The purpose of this article is to cover all aspects of unit healing inCiv4. Although it was written for Vanilla Civ 4, it includes
information relevant to the Warlords expansion.
If you accessed this article through the War Academy, it may be worth checking the associated thread for updates.
I welcome any feedback. Please post to direct my attention to anything which is not accurate. Don’t hesitate to add any tips you think would benefit the article or make it more comprehensive.
I have included a list of useful tips/observations at the conclusion of the article for your convenience.
The term friendly will be used in this article to describe a civ with whom you are at peace. Allied civs include teammates and civs with a permanent alliance.
A unit which is damaged (less than 100HP) and eligible (see below) for healing will be healed at the beginning of the next turn, after all other AIs/players/barbarians have had their turns. An eligible unit will stop healing only when it reaches 100HP.
A unit is eligible for healing if it “forfeits” its turn. More explicitly, there are actions which disqualify a unit from being eligible for healing, and actions which have no effect on a unit’s eligibility. Details below:
Eligibility for Healing
A unit that performs ANY of the following actions will NOT be eligible for healing:
- Movement (this does not include the indirect movement of cargo in transports)
- Attack
- Pillage
- Bombard
- Load or unload (including from ship to ship)
- Airlift
- Bombing/Air Strike (air units)
- Reconnaissance (air units)
- Re-basing (air units)
- Upgrade
EXCEPTION: The March promotion
A unit with the March promotion is ALWAYS eligible for healing. Any of the above actions which ordinarily disqualify a unit from being allowed to heal instead have no effect. For example, a March-promoted Cavalry can move 1 tile, attack, and then still be eligible for healing.
The following actions will not affect a unit’s eligibility for healing:
- Fortify
- Sleep
- Sentry
- Defending from an attack
- Sitting in a cargo ship while it moves
- Accepting a promotion
- Intercept Mission (air units)
In most documentation on unit healing, a unit will be said to heal some “percentage” in a turn. eg. the manual will tell you Medic I heals units on the same tile by 10%. The percent healed is the same as the number of HP healed. eg. A medic will add 10HP to units it heals.
A unit’s heal rate is determined by adding its Base Heal Rate to, if applicable, any medic healing, hospital healing and healing from Combat promotions. Details below:
Base Heal Rate
Eligible units will heal:
5HP per turn in enemy territory,
10HP per turn in neutral territory (but not a city). Note: Neutral territory includes unclaimed territory and the territory of friendly civs, but not allied civs.
15HP per turn in home/allied territory (but not a city) or in any city which is in resistance
20HP per turn in a city which is not in resistance
Medics
A unit with the Medic I promotion will heal all eligible units on the same tile by 10HP.
A medic can move and then heal units on the tile it ends its turn on.
A unit with Medic I heals itself if eligible.
A unit with Medic II will heal all eligible units in any adjacent tiles by 10HP. Minor note: a unit with Medic II but not Medic I will NOT heal units on the same tile.
IMPORTANT NOTE: Units with Medic II cannot heal units across a land/sea boundary. Ships in port are considered to be on the land side of the land/sea boundary.
No more than one Medic unit can operate on a unit eligible for healing each turn.
A unit with Medic I and II does not heal units on the same tile any quicker than if it had only Medic I.
Any ships (including transport ships) with Medic I will heal eligible units in their cargo or on the same tile.
A medic unit can heal land, air and naval units.
Medics can heal the units of an allied civ.
Minor note: The Red Cross wonder only gives the Medic I promotion to units which are ordinarily allowed to accept that promotion.
Warlords: In the Warlords expansion, the presence of a great general allows the Medic III Promotion for Medic II promoted units. The Medic III Promotion gives an additional 15HP of healing to units on the same tile and adjacent tiles, totalling 25HP.
Hospitals
A hospital will heal all eligible units on the same tile (city) an additional 10HP.
A hospital can heal land, air and naval units.
A hospital can heal all eligible friendly/allied units.
A hospital does not work in a city during resistance.
Combat IV and Combat V
A unit which has the Combat IV promotion and is eligible for healing will heal itself an additional 10HP if it is in neutral (including friendly civ’s) territory.
A unit which has the Combat V promotion and is eligible for healing will heal itself an additional 10HP if in enemy territory.
Note: Combat IV and Combat V do nothing when in home/allied territory (contrary to what one might expect). Both Combat IV and Combat V apply only when in the territory described above.
Promotion-Heal
Choosing a promotion IMMEDIATELY heals 50% of the HP needed to reach 100HP. If the number of HP needed is odd, the number healed is rounded down. Eg. a unit with 21HP will heal to 21 + (100 – 21) * 0.5 = 60.5 “=” 60HP
A unit need not be eligible for healing to receive the Promotion-Heal.
Accepting promotions has no effect on a unit’s eligibilty for healing, and the immediate Promotion-Heal is independent of the healing that happens at the beginning of your turn.
Extra Info
Upgrading a unit does not heal any HP.
AI units and barbarians heal the same way a player’s units do. For barbarians, all civs are enemies (for territory considerations).
Healing Formula
There are 4 parameters that affect a unit’s healing rate; Base Heal Rate, Medic, Hospital and Combat promotions (IV or V).
Let X be the number of HP a unit has which is eligible for healing.
Let P be the number of HP the eligible unit will heal. Then,
P = min(100 – X, B + M + H + C)
where
B = 5 if in enemy territory
B = 10 if in neutral or friendly territory (but not a city)
B = 15 if in home/allied territory (but not a city) or in a city during resistance
B = 20 if in a home/allied/friendly city not in resistance
M = 10 if a medic is available to operate on the unit (In Warlords, if the medic is Medic III then M = 25)
M = 0 otherwise
H = 10 if the unit is in a city with a hospital
H = 0 otherwise
C = 10 if the unit has Combat IV and is in neutral (or friendly civ’s) territory
C = 10 if the unit has Combat V and is in enemy territory
C = 0 otherwise
A unit with X hit points which is eligible for healing will heal to X + P hit points at the beginning of the next turn.
Let N be the number of turns required to heal a unit. Then,
N = ceiling[(100 – X) / (B + M + H + C)]
Note the formula always holds because B + M + H + C is never 0, and 0 < X =< 100.
N is the same as the number of turns the game will display for a unit to heal completely. Minor note: Units that are not eligible for healing will still display the same N so actually they will take N+1 turns to heal.
For those interested, the Promotion-Heal has the following (obvious) formula.
Let X be the HP of ANY unit which has a new promotion available. Selecting a promotion will IMMEDIATELY heal P hit points where
P = floor[(100 – X) * 0.5]
A unit will therefore have X + floor[(100 – X) * 0.5] hit points immediately after choosing a promotion.
Observations
- A unit in enemy territory will take 20 turns to heal if it has less than 5HP. This is the maximum number of turns a unit could take to heal.
- A unit in enemey territory will heal 3 times faster if he has a medic available. He will heal in 7 turns at the most, at a rate of 15HP per turn (as opposed to 5HP per turn without a medic).
- A unit without Combat IV will heal fastest in a home or friendly city, with a hospital and a medic of your own or ally’s (40HP per turn and maximum 3 turns to completely heal).
- A unit with Combat IV will heal faster in a friendly civ’s city than your own!
- The fastest any unit can heal is 50HP per turn. The unit must have Combat IV and be in a friendly civ’s city that has a hospital and a medic of yours or your ally’s. With this set up you will have a maximum heal time of 2 turns! 20HP from being in city, 10HP from medic, 10HP from hospital and 10HP from Combat IV. Total: 50HP
- March is generally a useless promotion for your medic units. It is often confused but you should give March to units which you will want to BE healed. For example, send along a Medic I Explorer with your Mech Infantry or March-promoted units and you will have a force which heals quickly when on the move even in enemy territory.
- If you have damaged units in a friendly civ’s territory, put them in one of the civ’s cities. These cities are just as good as your own cities at healing your units!
- Armored units and helicopters cannot be given Medic promotions. Armored units, helicopters and naval units cannot be given the March promotion. However, these promotions can be retained through unit upgrades eg. by upgrading march promoted cavalry to gunships.
- Often it is wise to hold off on promoting a unit so that after a battle the immediate (and significant) Promotion-Heal can be used.