Tech Levels are a crucial part of GURPS system, and of the Infinite Worlds setting. Very simply, they can be listed on a scale from Tech Level 0 (Stone Age) through Tech Level 8 (Digital Age) to Tech Level As High as the Game Master wishes (sci-fi). This is however complicated somewhat by a special nomenclature for split technologies (if a world is more advanced in some fields), and different technologies (psi, magic, science). This page will attempt to provide a brief overview. For full overview, see references.

What makes a Tech Level?Edit

'“Tech level” (TL) is a general rating of a society’s highest achievement in technology (or a certain type of technology).'(sic)

Please note that tech levels have somewhat changed between editions. The below chart is intended to represented the newest, 4th Edition. The biggest changes from 1st-3rd ed was the elimination of ending dates and the introduction of superscience. For an older version (3rd ed.) see

Also note that GURPS Lensman uses a totally different Tech level system called Tech Stages.

General Tech Level overviewEdit

TL Era Rough start date Signature technologies
0 Stone Age Prehistory and later Counting; oral tradition.
1 Bronze Age 3500 B.C.+ Arithmetic; writing.
2 Iron Age 1200 B.C.+ Geometry; scrolls.
3 Medieval 600 A.D.+ Algebra; books.
4 Age of Sail 1450+ Calculus; movable type.
5 Industrial Revolution 1730+ Mechanical calculators; telegraph.
6 Mechanized Age 1880+ Electrical calculators; telephone and radio;
7 Nuclear Age 1940+ Mainframe computers; television.
8 Digital Age 1980+? Personal computers; global networks.
9 Microtech Age 2025+? Artificial intelligence; real-time virtuality.
10 Robotic Age 2070+ Nanotechnology or other advances start to blur distinctions between technologies...
11 Age of Exotic Matter
12 Whatever the GM likes!

Tech Level by FieldEdit

TL Transportation Weapons and Armor Power Biotechnology/Medicine
0 Skis; dogsleds; dugout canoes. Wooden and stone weapons; primitive shields; hides for armor. Human muscle power; dogs. First aid; herbal remedies; primitive agriculture.
1 Bare horseback; the wheel (and chariots); ship-building; sails. Bronze weapons and armor. Donkeys; oxen; ponies. Surgery; animal husbandry; fermentation.
2 Saddle; roads; triremes. Iron weapons; iron armor (including mail); siege engines. Horses; water wheels. Bleeding the sick; chemical remedies.
3 Stirrups; oceangoing sailing ships (longships, roundships, etc.). Steel weapons; early firearms; plate armor; castles. Heavy horses and horse-collars; windmills. Crude prosthetics; anatomical science.
4 Stagecoach; three-masted sailing ships; precise navigation. Muskets and pikes; horse artillery; naval broadsides. Improved windmills; belt drives; clockwork. Optical microscope makes cells visible.
5 Steam locomotives; steamboats; early submersibles; balloons and early airships. Early repeating small arms; rifled cannon; ironclads. Steam engines; direct current; batteries. Germ theory of disease; safe anesthetics; vaccines.
6 Automobiles; continental railways; ocean liners; submarines; aircraft. Smokeless powder; automatic weapons; tanks; combat aircraft. Steam turbines; internal combustion; alternating current; hydroelectricity. Antibiotics; blood typing and safe transfusions; heredity; biochemistry.
7 Nuclear submarines; jet aircraft; helicopters; manned space flight. Ballistic body armor; guided munitions; combat jets; nuclear weapons. Gas turbines; fission; solar power. Discovery of DNA; organ transplants; pacemakers.
8 Satellite navigation; SSTO ("single stage to orbit") spacecraft. Smartguns; blinding lasers; unmanned combat vehicles. Fuel cells; advanced batteries. Genetically modified organisms; gene therapy; cloning.
9 Robot cars; space elevators; manned interplanetary space flight. Electrolasers; heavy laser weapons; battlesuits; combat robots; designer viruses. Micro fuel cells; deuterium-hydrogen fusion; high-temperature superconductors. Human genetic engineering; tissue engineering; artificial wombs; cybernetic implants
10 Fast interplanetary space flight. Compact laser and heavy particle-beam weapons; Gauss guns; nanotech armor; nanoviruses; antimatter bombs. Helium-3 fusion; antimatter. Brain transplants; uploading; bioroids; uplifted animals.
11 Manned interstellar space flight. Compact particle-beam weapons; disassemblers ("gray goo"); defensive nanites. Portable fusion power. Living machines; cellular regeneration.
12 Faster interstellar space flight. Gamma-ray lasers; "living metal" armor; black-hole bombs. Portable antimatter power. Full metamorphosis; regeneration.
^ Reactionless thrust; contragravity; faster-than-light (FTL) travel; matter transmission; parachronic technology; time machines. Monomolecular blades; force-field technology; gravitic weapons; nuclear dampers; disintegrators. Broadcast power; cold fusion; zero-point energy; total conversion; cosmic power. Fast-growth clone tanks; psi drugs; regeneration ray.

"Note that TLs have start dates but not end dates. The innovations of a given TL fade as those of higher TLs displace them, but they rarely vanish completely. A blacksmith in 1850s England uses TL3 techniques to shoe the horses that pull the carriage the gentleman rides to catch his TL5 train to London – and those techniques might still exist in TL8, albeit as a quaint hobby." B511

Borderline technology: TLOld-TLNew. Example: TL5-6. For societies in transition from one tech level to another.

Split technologies: TLPrimary (fields, TLSecondary). Example: TL8 (Communications TL7, Medical TL9). For societies more or less advanced in some fields.

Borrowed (familiar) technologies: TLKnown/Familiar. Example: TL1/2 (Bronze Age society familiar with Iron Age technology). For societies familiar with other level of technologies but not able (or willing) to replicate them.

Divergent technology: TL(Historical+Divergent). Example: TL(5+1) is a TL6, with historical Earth-like TL5, but somewhat different TL6 (same effects, different form). For alternate worlds which "look" different. Characters not used to divergent technology suffer a -2 penalty. The closet real world example is Edison's 1896 Kinetophone (called a Speaking Mutoscope in SteamTech pg 52) at TL(5+1) when contrasted to Lauste's 1907 sound on film method at TL6. (The first use mechanical means so common to TL5 to sync picture and sound while the second uses electrical means that would be common in TL6)

Outside the normal TL scale (superscience): marked by ^. These are technologies that violate our current understanding of physical laws (relativity, conservation of energy, etc.). For this reason any TL assigned to them is arbitrary. So FTL travel can be TL6^, TL(6+4)^, TL10^ or something else entirely depending on the setting. This is why broadcast power has two totally different TLs: TL6^ (Infinite Worlds, Gernsback) and TL10^ (Ultra-Tech).

Tech level modifiers (for characters using technology more / less advanced): if based on IQ -5 for each +1TL, -2 for each -1TL, -1 if not (it is assumed that non-IQ skills don't require that many things to figure out).

Figuring out 3e TLs in 4eEdit

The change in the TL scale between GURPS 3e and GURPS 4e resulted in many future TLs being classified as Alternate technology and many divergent technologies (such in Steampunk) being folded into the standard TL scale or becoming superscience. As a result many of the future TLs in GURPS 3e books don't quite line up with 4e TLs causing problems. David L. Pulver provided very rough conversion chart in the GURPS forums.

It should be mentioned that dates in either TL system are approximations:

Television, which GURPS states is a TL7 device, goes back to 1909 which is firmly in the realm of TL6. Furthermore the first commercial TVs similar to what we would recognize appeared in the 1930s and were used to show the 1936 Summer Olympics and the coronation of George VI in 1937.

Similarly, personal computers (TL8) appeared before 1980+: Xerox PARC's Alto (1972), MITS Altair 8800 (1975), and the Apple II (1977) are some of the better remembered ones today.

Heck, we have fledgling artificial intelligence and robot cars (TL9) right now...well before the 2025+? date given by GURPS. Also GURPS puts fuel cells at TL8 even though the first reference of them occurs in 1838...well in TL6. The Gemini and later Apollo spacecraft used fuel cells and that is firmly in TL7.

GURPS puts alternating current is TL6 (1880+) but first alternating current generator was invented in 1832 and the first public use of AC systems were in the late 1870's...well before the "start" date for TL6.

The Steampunk/Streamtech issueEdit

It doesn't help that Steampunk and Steamtech seemed to have taken the tack of 'it was TL6 but invented/designed before 1900 or could appear earlier then it did in our world and is therefore is TL(5+1)'. These are all historical items given the TL(5+1) label that could be just as well be "normal" TL5 or TL6:

Item Yearbook reference
H.M.S Dreadnaught 1906 (Lunched) Steampunk 79
Acetylsalicylic Acid


1899 Steampunk 92
Bactericide (chemical)

Penicillin (biological)

early 19th century


Steampunk 92

Electropathic Belt[2] 1850s Steamtech 31
Dewar Flask


1892 Steamtech 42
Tempest Prognosticator[3] 1851 Steamtech 51

Howitzer 1914[4] Steamtech 98
Long Range Cannon 1918 Steamtech 98

(as Anesthesia)

1898 (gas)


Steamtech 109
Bakelite 1907 Steamtech 115

Equivalent TL (Magic and Superscience)Edit

GURPS 4e Fantasy introduced the concept of Equivalent TL where magic is so common (in the form of spells or magic items) that it effects the TL as it may be on par with TL10 in one place but struggling to reach TL5 in others.

This makes the actual TL difficult to determine. "Look at a number of commonly used spells, assign them to approximate TL equivalents, and see if these cluster around one or two TLs as usually defined; if so, use a rough equivalent TL in that range. If that doesn’t work, the TL concept may not fit the setting. (...) Settings with magically based TL ratings are effectively alternative histories, where the point of departure is the invention of reliable magic."

Note that "magic" can also include superscience as it also involves the violation of accepted physical laws. So you can have the above method say one thing but it is actually something different.

For example, take Etheria where limited manned interplanetary exists. This is normally TL9 but the world is actual TL(5+1)^ (etheric spacecraft, TL5^) or 3 to 4 TLs below what would be "normal".

Sometimes a setting may give clues regarding its "base" TL (both Star Trek and Star Wars do this with very esoteric information) but most often one is left to their own judgement.

Pyramid™ ThemesEdit

Pyramid groups TLs into three 'themes' which it alternates between with each issue[1]. These themes are a useful way of roughly describing the time period,
  • Fantasy/Past TL0 through TL4 (up to 1700 AD)
  • Modern TL5 through early TL8
  • Space/Future TL8 and beyond
These are 'rough' because for example Modern goes from the 1700s through to early 2000s, so Modern includes everything from cowboys in the wild wild west to Neil Armstrong and the first moon landing.


  1. 'Pasteur gravely announced: “That there were high hopes for the cure of disease from this experiment,” but that is the last you hear of it, for Pasteur was never a man to give the world of science the benefit of studying his failures.' (Paul de Kruif's 1926 book Microbe Hunters)
  2. If it works then it is superscience
  3. If it works then it is superscience
  4. There were "Howitzers" before this date. The flavor text shows this is the Big Bertha design.