Where civilization stands
Measured, not asserted: humanity's energy use placed on the Kardashev scale, and the numbers that say whether that energy is making lives longer, safer and better informed without wrecking the planet. Updated once a year from the agencies that publish them.
On the Kardashev scale
In 2025 humanity used 177,865 TWh of primary energy, an average of 2.03×1013 W.
K = (log₁₀ P − 6) ÷ 10, with P the power a civilization uses, in watts (Sagan, 1973). Each 0.1 is ten times more power.
| Type | Power | What it means | From today |
|---|---|---|---|
| I | 1016 W | The energy a whole planet can put to use | 493 times today |
| II | 1026 W | The output of a star: the Sun radiates 3.828×10²⁶ W (IAU nominal solar luminosity, 2015) | 4.9×1012 times today |
| III | 1036 W | The order of a galaxy's stellar output | 4.9×1022 times today |
Kardashev defined three types. "Type IV" and above are later informal extensions with no agreed definition and nothing that can be measured, so this page shows them as a direction, not a threshold.
The climb since 1800
1800: 0.581 · 1900: 0.614 · 1950: 0.650 · 2000: 0.713 · 2025: 0.731
The numbers behind the chart
| Year | Primary energy (TWh) | K |
|---|---|---|
| 1800 | 5,653 | 0.581 |
| 1810 | 5,961 | 0.583 |
| 1820 | 6,264 | 0.585 |
| 1830 | 6,653 | 0.588 |
| 1840 | 7,300 | 0.592 |
| 1850 | 7,791 | 0.595 |
| 1860 | 8,005 | 0.596 |
| 1870 | 8,592 | 0.599 |
| 1880 | 9,519 | 0.604 |
| 1890 | 10,659 | 0.608 |
| 1900 | 12,101 | 0.614 |
| 1910 | 15,617 | 0.625 |
| 1920 | 17,963 | 0.631 |
| 1930 | 19,837 | 0.635 |
| 1940 | 22,528 | 0.641 |
| 1950 | 27,972 | 0.650 |
| 1960 | 40,589 | 0.667 |
| 1970 | 64,365 | 0.687 |
| 1980 | 84,853 | 0.699 |
| 1990 | 103,124 | 0.707 |
| 2000 | 118,481 | 0.713 |
| 2010 | 147,912 | 0.723 |
| 2020 | 159,194 | 0.726 |
| 2025 | 177,865 | 0.731 |
Energy is not the whole measure
A civilization that doubles its energy while its children die is not more advanced. The latest value of each measure, with its course since 1990 or since records begin.
Energy
How much power humanity commands, and how clean it is.
Wellbeing
Whether the energy reaches people as longer, safer lives.
Knowledge
Whether people can read, reach and add to what is known.
Sustainability
Whether it can continue.
The ladder on the same scale
Energy used per person per day is the one measure that runs from a hunting band to today, so it places each tier of the ladder, and a rebuilding community, on the same line as history. Energy used per person per day, food included, in kilocalories.
| Stage | When | kcal per person per day | Tiers | |
|---|---|---|---|---|
| Primitive Food only | 1,000,000 BC | 2,000 | before the ladder | |
| Hunting Food 3,000; fire and tools 2,000 | 100,000 BC | 5,000 | Tier 0 | |
| Primitive agricultural Food 4,000; home 4,000; farming 4,000 | 5000 BC | 12,000 | Tier 1 | |
| Advanced agricultural Food 6,000; home and trade 12,000; farming and industry 7,000; transport 1,000 | AD 1400 | 26,000 | Tier 3 | |
| Industrial Food 7,000; home and trade 32,000; industry and farming 24,000; transport 14,000 | AD 1875 | 77,000 | Tier 4 | |
| Technological Food 10,000; home and trade 66,000; industry and farming 91,000; transport 63,000 | AD 1970 | 230,000 | Tier 5, Tier 6, Tier 7 | |
| World average today Energy supply only: food and traditional biomass are not counted | 2025 | 47,700 | — |
Tier 2: Bronze and Iron Age societies sit between Cook's primitive (12,000) and advanced (26,000) agricultural stages; he gives no figure for them. The world average sits below Cook's 1875 industrial stage: the average hides the gap between those who have modern energy and those who do not. Cook, E. (1971). The flow of energy in an industrial society. Scientific American 225(3), 134–144. ↗
The horizon
The ladder stops where today stops, because every step on it must be something people can do. What lies beyond is a list of milestones that can each be checked.
| Milestone | Criterion | Status |
|---|---|---|
| K = 0.8 | Humanity uses 10¹⁴ W | Not met: needs 5 times today's energy |
| K = 0.9 | Humanity uses 10¹⁵ W | Not met: needs 49 times today's energy |
| Type I, K = 1.0 | Humanity uses 10¹⁶ W | Not met: needs 493 times today's energy |
| Back inside the planetary boundaries | No planetary boundary transgressed | Not met: 7 of 9 transgressed (Planetary Health Check 2026), the most ever recorded · source ↗ |
| Electricity from fusion | A fusion plant sends more electricity to the grid than it draws | Not met. Ignition, with more energy out of the fuel target than the lasers delivered to it (3.15 MJ from 2.05 MJ), was first reached at the US National Ignition Facility on 5 December 2022; the facility drew far more than that from the grid · source ↗ |
| People living off Earth without a break | A crew in space continuously | Met since 2 November 2000 (International Space Station), wholly supplied from Earth · source ↗ |
| A self-sustaining settlement beyond Earth | People living off Earth who could survive if supply from Earth stopped | Not met |
| Type II, K = 2.0 | Using 10²⁶ W, about a star's whole output | Not met: needs 4.9×1012 times today's energy |
| Type III, K = 3.0 | Using 10³⁶ W, the order of a galaxy's output | Not met: needs 4.9×1022 times today's energy |
| Type IV and beyond | No agreed definition | Speculative: a direction, not a measurable threshold |
Sources and record
Kardashev, N. S. (1964). Transmission of information by extraterrestrial civilizations. Soviet Astronomy 8, 217. Sagan, C. (1973). The Cosmic Connection: An Extraterrestrial Perspective. Doubleday. The continuous form of the scale.
What this page has said
- 2026-09-26: K = 0.731 for 2025