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This article is considered accurate for the current version (1.5) of the game.

A planet's population is the center of productivity and political action. Planets are made up of Population Units (POPs), each of which exists on a specific tile on a specific planet. Tiles that have buildings must also be occupied by a POP in order for the building's effects to be active.


Any planet with at least one unoccupied tile will generate its population naturally unless blocked by a policy or right. New pops grow one at a time, and the growing pop is represented by a translucent form of the corresponding species on an unoccupied tile, with a blue bar underneath representing the growth progress. New pops will prioritize appearing on tiles that produce resources. If no such tile is available, it will appear on any empty tile that is not blocked. The growing pop can be relocated on another tile in advance.

As of update 1.5, food surplus produced on all planets is placed in a 'global' food stockpile, used to feed the entire empire. When a planet uses more food than it produces, this amount is subtracted from the stockpile. The maximum size of the stockpile depends on the food stockpiling policy.

When the stockpile is neither full nor empty, the growing pop will progress toward complete at a rate of 1.0 growth point per month. It does not matter if a planet on its own consumes more food than it produces. Growth points are generated at a rate based on food surplus/shortfall. Once the food stockpile is full, any additional food produced is instead converted into faster Pop growth across the empire at a rate relative to the size of the population (so an excess of 5 food per month will produce much more growth in a 10 Pop empire than in a 100 Pop empire). When the food stockpile runs out, all population growth in the empire is halted and biological pop happiness is decreased. The exact mechanics are as follows.

Growth points required for a new pop:

(25 + \text{size penalty}) \cdot (2 - \text{habitability} + \text{growth rate})

So a planet with 15 pops, 80% habitability and the rapid breeders trait (-10% growth time) on the pop in question takes (25 + 45.4) * (2 - 0.8 + -0.1) = 77.44 growth points for the next pop.

The size penalty is based on the current population on the planet p and is equal to

1.65p + p^{1.12}

Current Size Point Penalty
10 29.6
9 26.5
8 23.4
7 20.3
6 17.3
5 14.3
4 11.3
3 8.3
2 5.4
1 2.6
Population points per month

Each month, a growing pop will progress towards the total amount of growth progress needed for the pop to become 'fully grown'. If there are multiple pop species growing on a planet, the progress points per month will be split by percent of fully grown pops of each species on the planet.

Excess food per month Stockpile Population Points
Less than 0 Empty No growth (Starvation)
Less than 0 Between full and empty 1 per month
Less than 0 Full 1 per month
At least 0 Empty 1 per month
At least 0 Between full and empty 1 per month
At least 0 Full 1 per month + an extra amount

The extra amount of growth with a surplus food production is based on the following formula:

0.5 \cdot \frac{\text{Food surplus}}{\text{Empire population}}

The maximum extra growth per month amounts to 2 growth per month (for a maximum total of 3). When calculating this value, it is always counted with having 10 as minimum amount.


Each pop in an empire has a base happiness rating. The happiness level of a faction determines the base happiness of all pops belonging to it. This means that where any pop not belonging to a faction has a base happiness of 50%, and a pop belonging to a faction that have their happiness reduced to 35% because of their issues will have a base happiness of only 35%. This base happiness then has all sorts of modifiers applied to determine the final happiness rating of a pop. An unhappy pop is less productive than a content one, and produces more unrest. The max happiness of a pop is determined by its habitability on a certain planet, even if the base happiness is higher than the habitability. On a planet where a species has 40% habitability, the species can only have a maximum of 40% happiness.

The base happiness of a faction, and therefore any pop belonging to it, is determined by how an empire treats a certain faction. Factions have issues related to their values and goals, and how well the empire responds to those issues will determine the overall happiness level of the faction. More details on the specifics of this system can be found on the factions page. In general, adhering to a factions demands will increase happiness, while ignoring or doing the exact opposite of their wishes will decrease their happiness rating. Factions with ethics clashing with the government ethics will also have decreased happiness.

A pop's base happiness is then modified by additional factors, such as civics and rights. Recently conquered populations will tend to be unhappy. Slaves will also gain additional unhappiness, depending on what type of slavery they are being subjected to. When an empire is starving, all biological pops gain unhappiness.

There are, fortunately, also many ways to improve happiness in an empire. Certain edicts issued at the governmental or planet level can raise the happiness of citizens throughout the empire or on the affected planet. Some government types can build structures that improve happiness at a planetary level.

Events may also have an impact on planetary happiness for a limited time.


Name Mod pop happiness.png Happiness Food.png Food Energy Credits.png Energy Minerals.png Minerals
Physics Research.pngSociety Research.pngEngineering Research.png Research
Happy 61 or greater Up to +20% Up to +20%
Content 40 to 60
Unhappy 39 or lower Up to -20%

Happiness Bonus and Penalties have no effect when the pop is enslaved.

Happiness modifiers[edit]


Name Value Cause
Social Welfare Programs +15% Empire has enacted the "Social Welfare Programs" edict
Idealistic foundation +5% Empire has idealistic foundation civic as government civic
Inwards perfection +5% Empire has inwards perfection civic as government civic
Improved Energy Initiative +5% Empire has enacted the "Improved Energy Initiative" edict (available through event)
Champion of the People +10% Ruler has Trait ruler champion of the people.png Champion of the People trait
Synthetic +10% Ruler has Trait robotic 3.png Synthetic trait
Starvation -10% Empire is starving
Riggan spice +5% Empire has access to the riggan spice strategic resource from a trader enclave
Grand Design +10% Possible outcome from researching Void Clouds as a Fanatic Spiritualist.png Fanatic Spiritualist or Spiritualist.png Spiritualist (10 years)
The Tree +5% Possible outcome from special Project "The Tree", the other choice is leader lifespan +20 years
Salty +10% Temporary bonus from researching an anomaly
Purple Rains +10% Temporary bonus from researching an anomaly
Extradimensionals/Prethoryn defeated +20% Gained for beating the Unbidden or Prethoryn crisis
Influence deficit -20% Empire influence is at 0 and has a negative monthly gain


Name Value Cause
Consecrated worlds +10% planetary edict from the consecrated worlds ascension perk
Propaganda Broadcasts +10% Planet has enacted the "Propaganda Broadcasts" edict (available unless Fanatic Collectivist.png Fanatic Collectivist)
Peace Festivals +10% Planet has enacted the "Peace Festivals" edict (available if Fanatic Pacifist.png Fanatic Pacifist)
Champion of the People +10% Governor has Trait ruler champion of the people.png Champion of the People trait
Dangerous wildlife -5% Planet has dangerous wildlife modifier
Hazardous Weather -5% Planet has Hazardous Weather modifier
Unstable Tectonics -5% Planet has Unstable Tectonics modifier
Wild Storms -5% Planet has Wild Storms modifier
Natural Beauty +5% Planet has Natural Beauty modifier
Irradiated -20% Planet has Irradiated modifier
Atmospheric aphrodisiac +10% Planet has atmospoheric aphrodisiac modifier (from event)
Comet Sighted +10% Comet Sighted Event (temporary)
Recent Impact -5% Event (temporary)
Recent Tectonic Event -5% Earthquake! Event (temporary)
Damaged ecology -2% Planet modifier
Friendly trees +2% Planet modifier
Abandoned terraforming -10% Planet modifier
[Gaia] world +20% Modifier from a specific kind of planet
Mutant stalker -10% Planet modifier from event
Wasteland radiation -10% Planet modifier, does not affect non-biological pops
Uncertain past -15% Planet modifier
Magnetic disruption -5% Event (temporary)


Name Value Cause
Communal +5% Has the Communal.png Communal trait
Solitary -5% Has the Solitary.png Solitary trait
Fertile +5% Has the Fertile.png Fertile trait
Charismatic +5% Modifier from pops with Charismatic.png Charismatic trait. Does not affect own species.
Repugnant -5% Modifier from neighboring pops with Repugnant.png Repugnant trait. Does not affect own species.
Recently Conquered -25% POP was recently conquered by its current empire (lasts 10 years)
Uplifted +20% If the pop is an Uplifted Pre-FTL species and is living on a planet ruled by their patron species
Enslaved -10/20/30% depending on the type of slavery If the pop is Enslaved
Citizenship -5% with residence rights, -10% with caste system (residence) rights What citizenship rights are given to a certain species
Living standards +40/20/10/0/-10/-20% depending on rights level What living standards are given to a certain species
Population controls -20% when population controls are enabled Whether a species is allowed to grow its population or not


Name Value Cause
Building xeno zoo.png Xeno Zoo +10% The planet has a Xeno Zoo building worked by a pop
Building symbol unity.png Symbol of unity +5% The planet has a symbol of unity building worked by a pop
Building paradise dome.png Paradise Dome +10% The planet has a Paradise Dome building worked by a pop (available only to empire with the utopian dream harmony)
Building religious monument.png Plague Memorial +10% The planet has a Plague Memorial building worked by a pop (available through event)
Building akx worm 2.png Loop Institute +10% The planet has a Loop Institute worked by a pop (available through event)
Building akx worm 1.png Spiral-Feed Power Hub −5% The planet has a Spiral-Feed Power Hub worked by a pop (available through event)
Building modern 1.png Ministry of Culture +10%

The planet has a Ministry of Culture worked by a pop (available through event)

Building zanaam obelisk.png Art Monument +10%

The planet has a Art Monument worked by a pop (available through event)

Building zanaam obelisk.png Stellar Devourer Trophy +5%

The planet has a Stellar Devourer Trophy worked by a pop (available through event)

(unrecognized string “dragonslayer monument” for Template:Icon) Dragonslayer Monument +10%

The planet has a Dragonslayer Monument worked by a pop (available through event)

(unrecognized string “ether drake shrine” for Template:Icon) Ether Drake Shrine +10%

The planet has a Ether Drake Shrine worked by a pop (available through event)


A pop that is on a tile that produces no resources is considered "unemployed" and should be moved to a tile where it can be useful. Unemployed POP have a distinct icon on the bottom left corner of the tile. This may be a signal to remove blocked tiles or construct new buildings. Unemployed pops are more likely to migrate if permitted. When there are unemployed pops in the empire, an alert will be displayed.

Ethics divergence[edit]

A materialist pop may decide to follow a more spiritual path and a pacifist culture might decide that peace is the path of the weak. This is called ethics divergence. Each pop in an empire will only embrace a single, non-fanatic ethic. At the start of the game, the population will be made of the ones that were picked. As population expands and eventually is divided over various planets and sectors, certain segments may decide to adopt values that are different from the core values of the species due to various circumstances in and around the empire.

Each ethic has a certain attraction value attached for all pops, depending on both the empire's situation and their own. For example, enslaved pops tend to become more egalitarian. Conversely, fighting a lot of wars will increase the attraction for militarism across the entire empire. The exact values and options that influence the attraction levels of certain ethics can be found at ethics attraction.

The attraction factors of ethics can be amplified by certain actions such as enacting policies or having traits. Especially the governing ethics attraction can be modified. Having a positive ethics attraction effect will let all actions that increase attraction to the government ethics result in even more attraction, and negative amounts will be decreased. With a modifier of 50%, an action that would increase attraction by 2 would instead increase by 3.

Ethics attraction modifiers[edit]

Government Ethics Attraction[edit]

Name Value Cause
Exalted Priesthood 20% Having the Civic exalted priesthood.png Exalted Priesthood civic.
Encourage Free Thought -15% Empire has enacted the "Encourage Free Thought" edict.
Information Quarantine 25% Empire has enacted the "Information Quarantine" edict.
Spiritualist 15% / 30% Has Spiritualist.png Spiritualist or Fanatic Spiritualist.png Fanatic Spiritualist as government ethic.
Psionic 10% Empire has a leader with the Leader trait psionic leader.png psionic trait.
Chosen 10% Empire has a leader with the Leader trait psionic chosen one.png chosen one trait.
Puppet 10% Gained from being a puppet.
Muutagan Crystals 10% Empire has traded with a merchant guild for access to the Muutagan.png Muutagan crystals strategic resource.
Satramene Gas 10% Empire has access to the Satramene.png Satramene gas strategic resource.
One Vision 30% Has unlocked the (unrecognized string “one vision” for Template:Icon) One Vision Ascension Perk.
Riots Averted 33% Riots have been dealt with.
Minor/Major Terrorist Action -33%/-75% A terrorist action has taken place due to high unrest.
Name Value Cause
Atmospheric Aphrodisiac -10% Planet has Atmospheric Aphrodisiac modifier.
Atmospheric Hallucinogen -10% Planet has Atmospheric Hallucinogen modifier.
Reeducation Campaign 20% Planet has enacted the "Reeducation Campaign" edict (not available to Fanatic Authoritarian.png Fanatic Authoritarian).
Social Engineering 30% Planet has enacted the "Social Engineering" edict (only available to Fanatic Authoritarian.png Fanatic Authoritarian).
Sector -10% Planet is managed by a Sector.
Capital World 100% Planet has Capital World modifier.
Distance -0.1% multiplied by the distance from the capital solar system A planet's distance from the capital solar system.
Orbital Mind Control Laser 50% Planet has a Spaceport with a Orbital Mind Control Laser module.
Name Value Cause
Base attraction -15% All pops have a basic of value of government ethics attraction.
Positive happiness Up to 20% Happy pops will be more attracted to the ethics of the government
Negative happiness Up to -20% Unhappy pops will be less attracted to the ethics of the government
Conformists 25% Has the Conformists.png Conformists trait.
Deviants -15% Has the Deviants.png Deviants trait.

Effects are Planet wide, unless otherwise mentioned.

Name Value Cause
Temple 10% Planet has a temple being worked by a pop (available only to Spiritualist.png spiritualist or Fanatic Spiritualist.png fanatic spiritualist).
Holotemple 15% Has a holotemple being worked by a pop (available only to Spiritualist.png spiritualist or Fanatic Spiritualist.png Fanatic Spiritualist).
Citadel of Faith 20% Has a Citadel of faith being worked by a pop (available only to Spiritualist.png Spiritualist or Fanatic Spiritualist.png Fanatic Spiritualist).
Ministry of Benevolence 10% Empire wide Has a Ministry of Benevolence being worked by a pop.
Reassembled Ship Shelter 5% Has a Reassembled Ship Shelter being worked by a pop.
Planetary Administration 15% Has a Planetary Administration being worked by a pop. Replaces Reassembled Ship Shelter.
Planetary Capital 15% Has a Planetary Capital being worked by a pop. Replaces Planetary Administration.
Empire Capital-Complex 15% Has an Empire Capital-Complex being worked by a pop. Replaces Planetary Capital.
Habitat Administration 20% Has a Habitat Administration being worked by a pop.
Ministry of culture 10% Has purchased monument via Artist patron event
Loop Institute 5% Has a Loop Institute being worked by a pop.

Non Government Ethics Attraction[edit]

Promoting a faction belonging to a certain ethic will increase all attraction factors to that ethic by 50%, while suppressing will instead lower all factors by 50%.

Consumer goods[edit]

Main article: Consumer_goods

Consumer Goods represents the portion of your industrial base that is occupied with seeing to the needs of your population, ie producing butter instead of guns. Each Pop in your empire will use a certain amount of Consumer Goods each month, with the amount primarily dependent on their living standards. Each unit of consumer goods costs a certain number of minerals dependening on factors such as ethics, traditions, whether your empire is engaged in a defensive war and so on. see main article for numbers


Main article: Slavery

Perhaps unsurprisingly, it is possible to enslave pops, depending upon ethos, policies, government, and the assorted species involved. Enslaving a pop causes it by default to produce more food and minerals, but means it generates extremely reduced (or no) Science and Energy, making it a significant tradeoff in terms of outputs. If the player has the Utopia.png utopia expansion enabled, there are 3 additional slavery that can be chosen. One type increases the happiness of free pops at a lower production, another allows for the creation of special armies and the final one makes a species become livestock.

More importantly, however, slavery can cause both internal and external strife; if the empire's citizens or neighboring empires are opposed to slavery (for instance because they are egalitarian) then this can cause serious civil and diplomatic issues.

Any pop can be enslaved, but it is best done on pops that are different from the starting species. All slaves are largely attracted to the egalitarian ethic, which may lead to them forming a large egalitarian faction that can have major influence in politics. Keeping slaves happy is crucial, as they can go on strike and even rebel when their happiness becomes too low. Slaves are also more prone to migrate.


As science progresses, creation of robot workers eventually becomes possible. They are exceptionally productive, easy to keep happy, and able to live and work on any planet surface - unlike most biological species.

All robotic workers cost 150 Energy Credits.png energy and 50 Minerals.png minerals to build. When built, they progress with a value of 1 per month until fully grown, one at a time per planet. They do not consume Food.png food; instead, they cost 1 Energy Credits.png energy each month. They have the Trait mechanical.png mechanical and appropriate Trait robotic 1.png robot traits. Their 200% bonus to habitability from the mechanical trait allows them to operate on any planet type equally well, even Tomb Worlds.

There are three tiers of robotic workers - Robots, Droids, and Synthetics;

  • Robots are the first and basic level of robotic workers. They have an advantage at producing Minerals.png minerals, but are disadvantaged at producing Energy Credits.png energy and produce very little Physics Research.pngSociety Research.pngEngineering Research.png research.
  • Droids are the second tier of robotic workers. They have a slight bonus to all yields compared to robots, excluding Food.png food.
  • Synthetics are the third and final tier of robotic workers. They are good at producing everything including Energy Credits.png energy and Physics Research.pngSociety Research.pngEngineering Research.png science apart, while having no malus to Food.png food production. Unlike Robots and Droids, Synths are sentient and can be granted (or, if oppressed, may demand) rights; doing so makes them equivalent to normal citizens in almost all respects. The only actions that a synth cannot perform is reproducing and being genetically modified.

The artificial intelligence policy dictates if robots can or cannot be built. When outlawed, no type of robotic worker can be made. When set on servitude, synthetics are enslaved and can be disassembled. The final option, citizen rights, lets synthetics have the rights of regular species. A certain degree of Materialist.png materialist is required for the citizen rights option to be selected.

If the Droids technology is unlocked, all owned Robots pops are automatically upgraded to Droids and the basic robots cannot be built anymore. The same is true for Synthetics.

Tier Tech prerequisite Can colonize planets Ethos and happiness Robotic trait Consumer Goods Cost Consumer goods.png Tile output
Minerals.png Minerals Energy Credits.png Energy Physics Research.pngSociety Research.pngEngineering Research.png Research Unity.png Unity
Alien AI.png Robot Tech robotic workers.png Robotic Workers No.png No.png
Trait robotic 1.png
None +10% -40% -80% -80%
Robot green.png Droid Tech droid workers.png Droids Yes.png No.png
Trait robotic 2.png
None +15% -20% -40% -40%
Robot blue.png Synthetic Tech synthetic workers.png Synthetics Yes.png Yes.png
Trait robotic 3.png
-25% +20% +20% +20% 0%

AI Rebellion[edit]

Robotic workers can be a major boon to the production of an empire. However, as research in Artificial Intelligence moves forward, there is a risk of robots gaining sentience and rebelling. This rebellion has a chance of infecting every robotic pop in the universe, prompting a galaxy wide war between flesh-and-blood empires and rogue computer intelligence. This is one of the possible major endgame crisis events. Granting robotic workers equal rights reduces their chances of rebellion -— or at least delays it -- but is not a guarantee that they will remain loyal.

The only way to keep synthetics loyal is by agreeing to the AI accord, which triggers anywhere from 70-100 years after anyone researches Sentient AI.



Migration is voluntary movement of POPs to a more attractive planet, for example a minority POP of aliens might try to move to its species homeworld. Once migration is activated for a POP, a modifier icon appears on its portrait in the planet surface view and after a certain amount of time it relocates to the destination. Fanatic Individualist empires have to allow free migration for their primary species. A migration access trade deal with another empire allows migration to foreign territory, in which case the empire of origin loses control over the moving POPs.


Resettlement is forced movement of POPs by the government. In order to resettle a POP an empire needs to activate the 'Allowed' Resettlement policy. After that, the resettlement menu can be opened through any POP. In this menu the planets and POPs involved in the resettlement can be chosen and the resettlement may be implemented at a cost of 50 Influence.png influence per POP. Resettlement is not available to Individualist empires. Since 1.3, resettlement does not require Planetary Administration, may be used with sector planets, and requires at least 40% Habitability.


As of 1.5 purging is done on a per species basis by setting the target species as undesirables, you cannot purge your primary species.[1]

With the right policies, undesirable species can be killed through purging. However, this angers most empires as well as other POPs. Depending on POP ethos, this reaction can be reduced or removed. Purging aliens will severely anger their original empire unless it has been conquered.

The purging policies may be set as

  • Displacement: The species is driven away through the use of forced resettlement and destruction of their homes. Displaced pops will not be killed, but rather will attempt to flee the empire to other, more welcoming empires, and might even try to settle uncolonized planets. This process is slow, but generates less outrage among other empires than the other forms of purging.
  • Extermination: The species is systemically killed off by any means available. This is the fastest form of purging, but pops subject to it are unable to produce any resources while they are busy dying off.

Additional purging policies are available by using the species rights

  • Forced Labor: The species is placed in camps and forced to do hard labor under brutal conditions with inadequate food and shelter, effectively working them to death. Pops doing Forced Labor will be killed off more slowly than through extermination, but will continue to produce minerals, food and (at a significant penalty) energy.
  • Processing: The species is processed into food for the consumption of other Pops. Pops being Processed generate a fixed amount of food and die off at a fairly fast pace, but cannot be put to use producing any other resources.
  • Neutering: The species is prevented from reproducing through chemical castration or biological modification, eventually dying off naturally. Neutered Pops continue to function normally and may even be given a high standard of life, but have a large penalty to their happiness. The speed at which they die off varies based on the species' natural lifespan, but is typically very slow.
Purge type Time taken to complete (months)
Extermination 60
Processing 120
Forced Labor 300

Neutering times .75 of leader death age (default is 72)

Default death time for species without a lifespan related trait is 54 years

Minimum time taken with a fleeting species will be .75* 46.5 years


Pops from other empires may flee to escape purges, slavery and resettlement. Whether or not another empire is willing to accept those fleeing depends on your Refugees policy. You can choose to accept other species will open arms, allowing refugee Pops to freely move into your empire, be more restrictive and accept only those Pops you have deigned to grant citizenship, or simply shut down acceptance of refugees altogether.

Refugees can be used to help grow your empire.


  1. https://forum.paradoxplaza.com/forum/index.php?threads/stellaris-dev-diary-57-species-rights.995302/
Game concepts
Governance EmpireGovernment typesPoliciesEdictsLeaderFactionsPopulation
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