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This article has been verified for the current PC version (3.4) 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 | edit source]

Technology interface. Every slot here can have one research project active at a time and every research area has its own slot.

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 | edit source]

The "card" system. Every time a research project is to be initiated, the game will draw a hand of cards like this one from which the player then can pick one technology to research.

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 less 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.

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.

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 is one basic parameter affecting a tech's chances of appearing in a given card hand:

  • 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, etc.) and its current state (scientist's traits, past tech, etc.).

To further increase variation, a tech which appeared as an alternative in the previous card hand will have its weight multiplied by 0.5 in the next draw.

As a rule of thumb, the more advanced a technology is, the lower its weight (and the higher its cost). Systematically important techs (e.g. terraforming) have a higher weight (typically between 150% and double normal) to help ensure empires get a chance to research them, whereas rare technologies have significantly lower weight (typically one-eighth normal without the matching expertise). Some factors increase the weight of rare techs:

  • Being in a level 3 or higher Federation research.png Research Cooperative federation with another member who knows the tech doubles the weight.
  • The Technological Ascendancy Technological Ascendancy ascension perk increases the weight of rare technologies by 50%.

Example[edit | edit source]

Let's assume the game draws a card hand of 3 techs: Armored Torpedoes Armored Torpedoes, Autocannons Autocannons, and Tech exotic gases.png Exotic Gas Refining. Additionally, the lead engineering scientist has a Propulsion.png Propulsion field expertise (matching Armored Torpedoes), and the previous card hand had Autocannons Autocannons as an available option.

If these were the only three valid techs and only one tech were to be drawn, then each tech's chances of being drawn would be 26.5%, 13.3%, and 60.2% respectively (rounded to 1 decimal place). Realistically there are usually many more valid picks and so the probability of picking any given tech is significantly lower than the figures given here.

Research alternatives[edit | edit source]

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

  • Menu icon edicts.png Scientific Revolution unity ambition
  • Tech self aware logic.png Self-Evolving Logic technology
  • Science Division Science Division / Mindlink / Research Path Optimization discovery tradition
  • Civic technocracy.png Technocracy civic
  • Civic natural neural network.png Natural Neural Network civic
  • Civic machine predictive analysis.png Static Research Analysis civic
  • Federation research.png Research Cooperative level 2
  • Scholarium Scholarium

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 from 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 losing research progress – and continue researching it at a later time. It is important to note, however, that the saved progress does not scale with changes to technology costs (for better or for worse). This tends to lead to the tech's completion percentage getting lower as the empire increases its Empire sprawl.png empire size.

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

Research output[edit | edit source]

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

Each of these individual resources has a base production of 10 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 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.pngPm frame 3.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.pngPm frame 2.png Wild Storms
+15% Natural Physicists.png Natural Physicists
  • "Prismatic Lenses" modifier
  • Pm strong magnetic field.pngPm frame 1.png Strong Magnetic Field
Society research Population Governance Planet Technology
  • Pm dangerous wildlife.png Odd Animal Life
  • Pm titanic life.pngPm frame 1.png Titanic Life
  • "Pharmaceutical Innovation" modifier
  • Pm dangerous wildlife.pngPm frame 2.png Hostile Fauna
+15% Natural Sociologists.png Natural Sociologists
  • "Well Rested Scientists" modifier
  • Pm atmospheric hallucinogen.pngPm frame 2.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 | edit source]

Whenever research output is not actively used, it accumulates as stored research. Stored research also includes research resources gained from other avenues, such as debris analysis, anomalies, events, etc.

This allows for a more "relaxed" approach research by eliminating the possible 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.

Stored research effectively doubles research speed, as it is spent at a rate matching current output, as long as there is enough stored research.


An empire produces Engineering research +24 engineering research each month and has just finished a 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 stored Engineering research engineering research will be completely depleted.

Research speed[edit | edit source]

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 effective 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.


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 Armored Torpedoes Armored Torpedoes.

Note: A research area without a leading scientist receives a −25% penalty to research speed.

Research Speed is affected by the following permanent or renewable modifiers. Other temporary modifiers to research speed may be gained from events or anomalies.

All research
Source Mod country all tech research speed.png Speed
Menu icon edicts.png Scientific Revolution edict +20%
Menu icon edicts.png Nanite Actuators edict +10%
Agenda Scientific Leap agenda +10%
Discovery tradition tree Discovery tradition tree finisher +10%
Technological Ascendancy Technological Ascendancy ascension perk +10%
Fanatic Materialist.png Fanatic Materialist ethic +10%
Materialist.png Materialist ethic +5%
Tech administrative ai.png Administrative AI +5%
Tech sentient ai.png Positronic AI (Gestalt consciousness.png Tech sentient ai.png Positronic Implants) +5%
Erudite.png Erudite ruler trait +5%
R worm scales.png Scales of the Worm relic triumph +20%
R galaxy.png Miniature Galaxy relic +5%
Federation research.png Research Cooperative level 2 +5%
Evt Science Nexus.png Science Nexus, per stage +5%
(+15% max)
Ancient Relics.pngFanatic Materialist.png Deeper Secrets of the Vultaum empire modifier +10%
Leviathans.png Eldritch Knowledge empire modifier +6.17%
Leviathans.png The Singularity Processor empire modifier +5%
Leviathans.png The Mirror of Knowledge empire modifier +10%
Leviathans.pngAncient Relics.png Curator Insight empire modifier +10%
Utopia.png Covenant: Whispers of the Void empire modifier +10%
Origins one the shoulders of giant.png Spurred by the Past empire modifier +5%
Origins one the shoulders of giant.png Full Circle empire modifier +5%
Origins one the shoulders of giant.png Goes Around, Comes Around empire modifier +5%
Overlord Building Ministry of Science holding +3%
Resolution technological sanctions.png Research Sanctions resolution, per level −5%
(−15% max)
Specific research fields
Source Mod country all tech research speed.png Speed Affects
Diplomacy research agreement.png Research agreement partner has researched tech +25% Specific tech
Civic devouring swarm.png Devouring Swarm civic +20% Biology.png Biology
Civic machine introspective.png Introspective civic +20% Engineering research Engineering
Menu icon edicts.png Master's Teachings: Philosophical Mindset edict +10% Society research Society
Menu icon edicts.png Improved Working Environment edict +10% Biology.png Biology
Statecraft.png Statecraft
Menu icon edicts.png Improved Energy Initiative edict +10% Industry.png Industry
Materials.png Materials
Menu icon edicts.png Numistic Visualization edict +10% Statecraft.png Statecraft
R worm scales.png Scales of the Worm relic +5% Physics Research Physics
R mechano calibrator.png The Defragmentor relic triumph +10% Engineering research Engineering
Ancient Relics.png Studying Polarian Seeds empire modifier +20% Biology.png Biology
Ancient Relics.png Secrets of the Irassians empire modifier +20% Biology.png Biology
Ancient Relics.png Secrets of the First League empire modifier +15% Industry.png Industry
Ancient Relics.png Secrets of the Vultaum empire modifier +15% Computing.png Computing
Ancient Relics.pngFanatic Materialist.png Deeper Secrets of the Vultaum empire modifier +15% Computing.png Computing
Ancient Relics.png Secrets of the Zroni empire modifier +10% Psionics.png Psionics
Leviathans.png Spectral Residue Studies empire modifier +5% Physics Research Physics
Overlord Salvager Insight empire modifier +15% Engineering research Engineering
Per Scientist.png scientist level +2% Assigned area
Expertise: <Subcategory> Scientist.png scientist trait +15% Subcategory
Leader trait lightbulb on.png Spark of Genius scientist trait +10% Assigned area
Leader trait sentient AI assistant.png Sapient AI Assistant scientist trait +10% Assigned area
Leader trait maniacal.png Maniacal scientist trait +5% Assigned area
Leader trait custom AI assistant.png Custom AI Assistant scientist trait +5% Assigned area
Leader trait paranoid.png Paranoid scientist trait −5% Assigned area

Technology cost[edit | edit source]

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 which is modified by Empire sprawl.png empire size. The research cost is increased by 0.1% for each point of empire size above 100.

Research progress[edit | edit source]

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.

Example[edit | edit source]

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

This setup generates the following monthly research progress:

Assuming no further changes 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, etc.

Debris[edit | edit source]

Debris has a chance of spawning when at least a ship from enemy fleet is destroyed. They are capable of providing progress on most of the components, weapons and defences, but not ship upgrades. The following are examples of technologies that cannot be obtained from debris:

  • Standardized Corvette Patterns
  • Improved Corvette Hulls
  • Destroyers
  • Synapse Interceptors
  • Psionics Shield

Each component can only spawn if the components are above the technology level of the attacker. Each component will provide 10% progress on the technology, or 10% progress on the pre-requisites technology if the pre-requisites technology is unresearched.

References[edit | edit source]

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