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This article has been verified for the current console version (2.2) of the game.

Technology in Stellaris is divided into 3 research areas with each area corresponding with one of the research resources: Engineering Research Engineering, Physics Research Physics and Society Research Society. Additionally, each of the ~300 techs belongs to one of 12 subcategories divided between the areas (most appearing pre-dominantly in one area though not exclusively).

The user interaction aspect utilizes a card shuffle approach rather than a traditional tech tree presentation, thereby introducing an element of semi-randomness into the system.

Research areas & fields[edit]

There are three different main research areas in-game, with each area corresponding with one of the research resources. Additionally, each research area has multiple subcategories, for a total of 12 such subcategories, and every tech belongs to one of these subcategories.

The areas and their subcategories are as follows:

Engineering Research Engineering research

  • Industry.png Industry: Mineral production and storage, robots, building construction.
  • Materials.png Materials: Armor, strategic resources.
  • Propulsion.png Propulsion: Kinetic and explosive weapons, thrusters.
  • Voidcraft.png Voidcraft: Ship types and hulls, starbases, strike craft.

Physics Research Physics research

  • Computing.png Computing: Science Labs, research, science ships, ship computers, point-defense, sensors.
  • Field Manipulation.png Field Manipulation: Power Plants, shields, some strategic resources.
  • Particles.png Particles: Ship reactors, energy weapons, FTL, some strategic resources.

Society Research Society research

  • Biology.png Biology: Food production, leader lifespan and policies, species modification, army types, some strategic resources.
  • Military Theory.png Military Theory: Fleet command limit, naval capacity, army buildings and statistics, claim cost.
  • New Worlds.png New Worlds: Tile blocker clearance, terraforming, starbase capacity, administrative capacity.
  • Statecraft.png Statecraft: Unity, edicts, leader pool and recruitment, planetary and empire capitals.
  • Psionics.png Psionics: Exotic mid- to late- game technologies. Unlocked through the Tech psionic theory.png Psionic Theory technology.

The card system[edit]

Although the underlying technology system is based on the familiar tech tree structure, it does away with its standard interaction/presentation in favor of the card shuffle approach. This injects a semi-random element into research, making it somewhat less predictable as well as more non-linear.

Whenever the player is prompted to initiate a research project, the game gives them a "hand of cards" consisting of a semi-random selection of technologies available for research which are picked randomly from a hidden "deck of cards" consisting of all valid research options that can appear.

Every time the player meets the requirements for a given technology to become obtainable, the technology in question is added into the main "card deck" and will then have a chance of appearing in the "card hand" whenever the game draws a new hand for the player to pick from. There are two basic parameters affecting a tech's chances of appearing in a given card hand:

  • Tiers - Technologies are divided into 6 levels (T0 to T5) of advancement. Higher tier technologies require obtaining a certain number of technologies from the preceding tier in the same area of research (set at 6 for all tiers[1]) before they become available as research alternatives.
  • Weight - A base value denoting the relative chance (out of all the valid options) of a particular technology to be drawn as an alternative. This may be further modified by an empire's composition (ethics, civics, and etc.) and its current state (scientist's traits, past tech, and etc.).

To further increase variation, a tech which appeared as an alternative in the previous card hand will have its weight set to 0 in the next prompt.

The range of costs for technologies in each tier is as follows:[2]

Tier Engineering ResearchPhysics ResearchSociety Research Cost Weight
1 2000 - 3000 90 - 100
2 4000 - 6000 70 - 85
3 8000 - 12000 50 - 65
4 16000 - 24000 35 - 45
5 32000 - 48000 20 - 30
repeatables 50000+ 12.5

As a general rule of thumb, the more advanced a technology is, the lower its weight (and the higher its cost).


Let's assume the game draws a card hand of 3 techs: Tech torpedoes 2.png Armored Torpedoes, Tech autocannons 1.png Autocannons, and Tech mine orillium.png Orillium Extraction. Additionally, the lead engineering scientist has a Propulsion.png Propulsion field expertise and the previous card hand had Tech autocannons 1.png Autocannons as an available option.

If a tech were to be picked at random, then each tech's chances of being drawn would be 28.7%, 12.3%, and 59% respectively.

Note: Tiers, weights, and what modifiers affecting it are hidden parameters. That being said, an expertise in a tech's field is likely to increase its weight (and therefore appearance).

Research alternatives[edit]

Each card hand drawn will contain 3 research alternatives. This may, however, be further increased by 1 for each of the following:

  • Menu icon policies and edicts.png Scientific Revolution unity ambition
  • Civic natural neural network.png Natural Neural Network civic
  • Civic machine predictive analysis.png Static Research Analysis civic
  • Tech self aware logic.png Self-Evolving Logic technology
  • Tradition discovery science division.png Science Division / Mindlink / Research Path Optimization discovery tradition

Additionally, some research cards may be gained as permanent alternatives. They appear below the regular alternatives and are distinguished from them by a golden border surrounding the tech card's bezel. These alternatives are usually acquired (along with some partial progress) through post-battle debris analysis, from special projects or event chains. These options will always appear as available options when drawing a new card hand and will remain as such until completed.

If need be, it is possible to change an on-going research project at any point - without incurring penalties - in order to continue researching it at a later time. It is important to note, however, that the saved progress does not scale with changes occurring to technology costs (for better or for worse). This tends to lead to the tech's completion percentage getting lower as the empire continues to expand.

As opposed to a permanent alternative, there is no guarantee that the technology in question will appear in the next card hand drawn.

Research output[edit]

Each research area employs the use of a different research resource.

Each of these individual resources has a base production of 5 research points a month. This can be further increased by pops working the appropriate Jobs or Module research stations on the galactic map.

The research production may then be modified by the following:

Research.png Population Governance Planet Technology
  • "Pleased" modifier
  • "Precursor Data Cache" modifier
  • Erudite.png Erudite
  • Trait robotic 3.png Synthetic
  • PM assist research.png Research Assistance (improved)
  • PM Strong Magnetic Field.png Magnetic Miracle
  • Menu icon policies and edicts.png Spirit of Science
  • "Curator Insight" modifier
  • Intelligent.png Intelligent
  • Logic engines.png Logic engines
  • Trait psionic species.png Psionic
  • Consumer goods.png Living standards – Academic privilege
  • Leader trait intellectual.png Analytical
  • Leader trait intellectual.png Intellectual
  • PM assist research.png Research Assistance
  • PM Irradiated.png Uncertain History
  • Module Observatory
  • Trait psionic species.png Latent psionic
  • Purge.png Labor Camps
  • Ghost Signal Ghost Signal
  • "AIs Patched" modifier
  • Menu icon policies.png AI – Servitude
  • "Stellar Culture Shock (early space age)" modifier
  • "War Protester" modifier
  • "Withdrawal Symptoms" modifier
  • Trait primitive.png Serviles
  • "Enraged" modifier
  • Ghost Signal Ghost Signal (2)
  • Ghost Signal Ghost Signal (machine 4)
  • Trait robotic 2.png Droid
  • Menu icon policies.png AI – Outlawed
  • Ghost Signal Ghost Signal (3)
  • Ghost Signal Ghost Signal (machine 5)
  • "Stellar Culture Shock (atomic age)" modifier
  • Slavery.png Battle Thralls
  • Ghost Signal Ghost Signal (4)
  • Consumer goods.png Living standards – Chemical Bliss
  • "Stellar Culture Shock (machine age)" modifier
  • Ghost Signal Ghost Signal (5)
  • Nerve Stapled.png Nerve Stapled
  • Slavery.png Chattel Slavery
  • Slavery.png Domestic Servitude
  • Trait robotic 1.png Robot
  • "Stellar Culture Shock (industrial age)" modifier
  • "Stellar Culture Shock" modifier

Additionally, each of the resources may also have the following modifiers affecting them (these apply only to a single resource rather than to all of them):

Engineering Research Population Governance Planet Technology
  • PM Unstable Tectonics.png Unstable Tectonics
  • Natural Engineers.png Natural Engineers
  • "Subterranean Tech Provision" modifier
Physics Research Population Governance Planet Technology
  • Dark Matter.png Dark Matter
  • PM Wild Storms.png Wild Storms
+15% Natural Physicists.png Natural Physicists
  • "Prismatic Lenses" modifier
  • PM Strong Magnetic Field.png Strong Magnetic Field
Society Research Population Governance Planet Technology
  • PM Dangerous Wildlife.png Odd Animal Life
  • PM Titanic Life.png Titanic Life
  • "Pharmaceutical Innovation" modifier
  • PM Dangerous Wildlife.png Hostile Fauna
+15% Natural Sociologists.png Natural Sociologists
  • "Well Rested Scientists" modifier
  • PM Atmospheric Hallucinogen.png Atmospheric Hallucinogen
  • PM Atmospheric Hallucinogen.png Filtered Atmospheric Hallucinogen
  • PM Hollow Planet.png Subterranean Civilization
  • "Loss of Personnel" modifier
  • PM faith in science.png AI Failure
  • PM Unknown.png Unproductive Without Experiments

Stored research[edit]

Research output which is not being used for research at the time is being accumulated as stored research. Alternatively, it may also include research resources gained from other avenues such as debris analysis, anomalies, events, and etc.

This method allows for a more "relaxed" research by eliminating the loss of research points due to forgetting to pick a research project while, at the same time, also simulating accelerated periods of research (as opposed to sudden "jumps") caused by newfound knowledge sources. The current storage levels can be seen by hovering over the appropriate resources.

The expenditure rate of stored research can be expressed as follows:


An empire produces Engineering Research +24 Engineering research a month and has just finished debris analysis granting it Engineering Research +1000 Engineering research (stored research).

The empire will supplement its Engineering Research Engineering research by an additional +24 research points for the first 41 months and by another +16 research points in the following month, after which the Engineering Research Engineering stored research bank will completely deplete.

Research speed[edit]

Research speed represents a given expertise in a particular research area or field leading to shortened research time of related technologies.

Research speed boosts the perceived research production in the following manner:

The most immediate sources of research speed modifiers are the 3 lead scientists. As the applied bonus depends on a scientist's skill level and overall traits, it is recommended to assign newly recruited scientists to command a science ship. Scientists on exploration duty tend to gain experience faster and, if one is in luck, they may also gain a new trait beneficial to research while leveling up.

The following table details the all-encompassing research speed modifiers while the one below lists limited scope modifiers:

Mod country all tech research speed.png Population Governance Planet Technology
  • "Covenant: End of the Cycle" modifier
  • Leader trait psionic chosen one.png Chosen One
  • "Boon of the Shroud" modifier
  • Leader trait curator.png Curator
  • "Covenant: Whisperers in the Void" modifier
  • "Extra Dimensional Insights" modifier
  • Fanatic Materialist.png Fanatic Materialist
  • Agenda Scientific Leap
  • Menu icon traditions.png Discovery tree completion
  • Ap technological ascendancy.png Technological Ascendancy
  • Leader trait psionic leader.png Psychic
  • Leader trait sentient AI assistant.png Sentient AI Assistant
  • Leader trait lightbulb on.png Spark of Genius
  • "Neural Bank" modifier
  • "The Mirror of Knowledge" modifier
  • Materialist.png Materialist
  • Leader trait custom AI assistant.png Custom AI Assistant
  • Leader trait cyborg.png Cyborg
  • Leader trait maniacal.png Maniacal
  • Trait robotic 3.png Synthetic
  • "Computational Overclocking" modifier
  • "The Singularity Processor" modifier
  • Building Research Institute
  • Building Singularity Core
  • Tech administrative ai.png Administrative AI
  • Tech sentient ai.png Positronic AI
  • "The Singularity Processor (hacked)" modifier
  • Leader skill levels.png Scientist skill (per level)
  • Leader trait paranoid.png Paranoid
  • "Curse of the Shroud" modifier
  • No acting lead scientist
  • "Energy Shortage" modifier
  • "Mineral Shortage" modifier
Mod country all tech research speed.png Limited scope modifiers Scope
  • Menu icon traditions.png Domination tree completion
  • (technology sharing with vassals)
Situation specific
+25% Situation specific
  • Civic devouring swarm.png Devouring Swarm
  • Civic machine introspective.png Introspective
  • Menu icon policies and edicts.png Engineering Research Grants
  • Menu icon policies and edicts.png Physics Research Grants
  • Menu icon policies and edicts.png Society Research Grants
  • Biology.png Biology
  • Engineering Research Engineering
  • Engineering Research Engineering
  • Physics Research Physics
  • Society Research Society
  • Field expertise traits
  • (one trait per corresponding field)
Field specific
  • Menu icon policies and edicts.png Improved Energy Initiative
  • Menu icon policies and edicts.png Improved Working Environment
  • Menu icon policies and edicts.png Master's Teachings: Philosophical Mindset
  • Industry.png Materials.png fields
  • Biology.png Statecraft.png fields
  • Society Research Society
+5% "Spectral Residue Studies" modifier Physics Research Physics

An empire is a Materialist.png Materialist and produces Engineering Research +24 Engineering research a month. It has a lead engineering scientist with a Propulsion.png Propulsion field expertise while researching Tech torpedoes 2.png Armored Torpedoes.

Note: A research area without an acting lead scientist receives a penalty to research speed.

Technology cost[edit]

As a game progresses, research option choices will begin to include progressively more advanced and correspondingly more expensive technologies.

Each technology has a base cost that applies as long as an empire does not exceed its Administrative Capacity. Once that happens the research cost will be increased by 0.3% for each point of exceeded Administrative Capacity.

This means that while overall an empire's research capabilities will increase with additional planets and systems, it will do so with increasingly diminishing returns for every new addition; Meaning, a larger empire will have to invest more resources than a smaller one to gain the same tech. This allows for empires of a somewhat differing size to keep a "relative" technological parity.

Research progress[edit]

In general, research time can be summarized as the following formula:

Research progress is one of the key elements affecting the time it takes to discover new technologies. It is formulated as follows:

While it is possible for the monthly research progress to remain constant during the course of researching a certain technology, it is more than likely to fluctuate - for better or for worse - due to consequences of various actions (such as exploration, empire development, expansion, etc.). This, in turn, may increase or decrease the total research time of a given tech.


The empire from the previous examples (same setup) has just finished debris analysis granting it +10% research progress in Tech torpedoes 2.png Armored Torpedoes along with Engineering Research +1000 Engineering research (stored research).

This setup will generate the following monthly research progress:

Assuming no further changes will impact the above setup, the total research time of the tech would be:

Note: Partial research can refer to debris analysis, previous research, event rewards and etc.


  1. See /Stellaris/common/technology/tier/00_tier.txt for details.
  2. See /Stellaris/common/scripted_variables/00_scripted_variables.txt for details.
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