Kardashev Clock

Earth · civilization energy index
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Sagan–Kardashev rating · K

0.7294000000
Type 0.73 72.94% of the way to a planetary civilization
Power draw19.690TW
Per year621.4EJ
Per person2,410W
Growth (now)+1.40% / yr
Log scale: each tick is 10,000× the last. Select a Type label for the details.

Time to each threshold

Select a Type to learn about it at 1.70% growth per year
I

Planetary

10¹⁶ W · all energy reaching a planet

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II

Stellar

10²⁶ W · a Dyson swarm around the Sun

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III

Galactic

10³⁷ W · the Milky Way's stars

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Impossible this fast: even light takes about 100,000 years to cross the galaxy.

Humanity's energy use since you opened this page

0 GJ
Counting up in real time.

This counter starts at zero when the page loads and adds up all the energy the world has used since then. It uses the power draw figure at the top of the page, about 19.7 TJ every second, and multiplies it by how long the page has been open.

That rate covers everything together: power stations, cars, planes, ships, factories, heating and cooking. It counts primary energy, which means the raw fuel and power before it is converted. For example, a coal plant loses about two-thirds of its coal's energy as heat before any electricity reaches the grid.

  • 1 GJabout the energy in 26 litres of petrol
  • 1 barrel of oilabout 6.1 GJ
  • Hiroshima bombabout 63 TJ, which the world uses every 3 seconds
I

Type I · K = 1.0

Planetary civilization

Threshold10¹⁶ W
Versus today—
From here—

How it's calculated

K = (log₁₀ P − 6) / 10
Δt = ln(Ptarget / Pnow) / r

K uses Carl Sagan's version of Kardashev's scale. The starting point is the world's measured primary energy use in 2025: 600.3 EJ, which averages out to about 19.0 TW. That is placed at mid-2025, then grown at 1.4% a year, the rise from 2024 to 2025, to estimate today's value. The slider only changes the forward projection.

Sources (10)
  1. 2025 energy use (600.3 EJ) and 2024 (592.2 EJ). Energy Institute, Statistical Review of World Energy 2026, released 2 July 2026. Figures as reported by Forbes.
  2. Growth cross-check (+1.3% in 2025, +2% in 2024). IEA, Global Energy Review 2026.
  3. Original scale. N. S. Kardashev (1964), "Transmission of Information by Extraterrestrial Civilizations", Soviet Astronomy 8, 217.
  4. K formula. Carl Sagan (1973), The Cosmic Connection. Summary on Wikipedia.
  5. Dyson swarms. F. J. Dyson (1960), "Search for Artificial Stellar Sources of Infrared Radiation", Science 131, 1667.
  6. Galaxy survey. R. L. Griffith et al. (2015), "The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. III", ApJS 217, 25.
  7. Tabby's Star. T. S. Boyajian et al. (2018), "The First Post-Kepler Brightness Dips of KIC 8462852".
  8. 1800–2000 history and the 1900 figure. J.-M. Martin-Amouroux, "World energy consumption 1800–2000: the results", Encyclopédie de l'énergie. Decade totals in Mtoe, including wood and other biomass; converted at 1 Mtoe = 41.868 PJ.
  9. The Sun's output (3.828 × 10²⁶ W). IAU 2015 Resolution B3, nominal solar luminosity.
  10. Population (~8.2 billion). UN, World Population Prospects 2024.

Some sources count energy differently, especially electricity from wind, solar and nuclear, so other estimates of today's total can differ by a few percent. That changes K only in the third decimal place.