Dyson swarm calculator

A Dyson swarm is a cloud of solar collectors orbiting a star. A full Dyson sphere around the Sun would capture all 3.828 × 10²⁶ watts of its output. Choose how much a swarm captures to see its size, mass and the computing it could run.

This calculator is about our real Sun, not the game Dyson Sphere Program.

Updated October 2026

Worked example

The results above when the page opens, step by step.

1. Power captured = 1% × 3.828 × 10²⁶ W = 3.83 × 10²⁴ W, about 1.89 × 10¹¹ times humanity's 20.2 TW in 2024.
2. Electricity = 30.7% × 3.83 × 10²⁴ W = 1.18 × 10²⁴ W.
3. Kardashev rating = (log₁₀(3.83 × 10²⁴) − 6) ÷ 10 = (24.583 − 6) ÷ 10 = 1.858.
4. Collector area = 1% × 4π × (1.496 × 10¹¹ m)² = 1% × 2.81 × 10²³ m² = 2.81 × 10²¹ m², 5.51 × 10⁶ times Earth's surface (5.10 × 10¹⁴ m²).
5. Collectors = 2.81 × 10²¹ m² ÷ 1 km² (10⁶ m²) each = 2.8 × 10¹⁵.
6. Mass = 2.81 × 10²¹ m² × 1 kg per m² = 2.81 × 10²¹ kg, 0.038 times the Moon's mass (7.346 × 10²² kg) or 0.0085 times Mercury's (3.301 × 10²³ kg).
7. Computing with today's chips = 1.18 × 10²⁴ W × 2,300 × 10⁹ FLOP/s per watt = 2.70 × 10³⁶ FLOP/s.
8. The physical ceiling on erasing bits: erasing one bit takes at least 1.380649 × 10⁻²³ J/K × 300 K × 0.693 (the natural log of 2) = 2.87 × 10⁻²¹ J, so 1.18 × 10²⁴ W ÷ 2.87 × 10⁻²¹ J = 4.09 × 10⁴⁴ bit erasures a second.

From swarm to computer

In the late 1990s Robert Bradbury described nested shells of computers around a star that would turn its whole output into computing, a “Matrioshka brain”. It is the closest older idea to Elon Musk's “sentient sun”: see What is a sentient sun?

The last two rows put rough numbers on it: the arithmetic today's chips would do on the swarm's electricity, in FLOP/s (calculations a second), and the most bits a second that physics lets any computer erase at the temperature you set (the Landauer limit). They measure different things, so they are never added or compared directly.

What this leaves out

• Whole arrays, not bare cells. Flown solar arrays, with their structure and wiring, weigh about 2 to 14 kg per m², worked out from NASA's survey of small spacecraft (see Method). Change the collector mass to see the difference.
• Aging. Radiation wears cells down in space; the efficiency here is for a new cell.
• Waste heat. Sunlight that isn't turned into electricity, and all the electricity once used, ends up as heat the swarm must radiate away. Radiators aren't counted.
• Orbits, spacing and shading. Collectors must not shade or hit each other; only the collecting area is counted.
• Building it. The materials, launches and time it would take are outside this calculator.
• Distance. Collectors sit at 1 au, Earth's distance from the Sun.

How it works

Power captured is your share of the Sun's whole output, 3.828 × 10²⁶ W (the International Astronomical Union's standard figure). At 1 au every square meter of collector catches about 1,361 W, so the area follows from the share. The share and the collector size are your choice; the other defaults are sourced, and you can change any of them under Assumptions.

The formulas, values and sources are on the method page: Dyson swarm and computing. To rate any power, or see when humanity would reach Type I, try the Kardashev calculator.