MW to GW Calculator

Convert megawatts to gigawatts instantly. 1 GW = 1,000 MW — the power scale of nuclear stations, national grids, and mega-dams.

MW
GW
1,000 MW = 1 GW

Gigawatts: The Language of National Energy Grids

Nuclear stations, mega-dams, and entire nations measured in GW

When power engineers discuss national electricity infrastructure, they switch from megawatts to gigawatts. One gigawatt (1,000 MW) is the approximate output of a single large nuclear power reactor — the kind of facility that anchors a region's electricity supply for 40–60 years. The typical pressurized water reactor (PWR), like those built by Westinghouse, produces 1.0–1.4 GW of continuous electrical output, running at over 90% capacity factor year-round regardless of weather or time of day.

Hydroelectric mega-projects push into double-digit gigawatts. The Three Gorges Dam spans the Yangtze River with 22.5 GW of installed capacity — enough to power all of Chile. The Itaipu Dam on the Brazil-Paraguay border generates 14 GW and supplies approximately 15% of Brazil's and 86% of Paraguay's electricity. In the renewable sector, countries track their total installed solar and wind capacity in GW: the United States surpassed 200 GW of combined wind and solar in 2024, while China leads globally with over 700 GW.

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Nuclear Reactors in GW

Power output of major nuclear reactor designs operating worldwide.

  • 🇫🇷 EPR (Flamanville/Hinkley): 1.6 GW
  • 🇺🇸 Westinghouse AP1000: 1.1 GW
  • 🇰🇷 APR-1400 (Barakah): 1.4 GW
  • 🇷🇺 VVER-1200: 1.2 GW
  • 🇨🇳 Hualong One (HPR1000): 1.15 GW
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Hydroelectric Mega-Dams

The world's largest dams measured in gigawatts of installed capacity.

  • 🇨🇳 Three Gorges Dam: 22.5 GW
  • 🇧🇷 Itaipu Dam: 14 GW
  • 🇨🇳 Xiluodu Dam: 13.86 GW
  • 🇧🇷 Belo Monte Dam: 11.23 GW
  • 🇻🇪 Guri Dam: 10.24 GW

MW to GW Conversion Formula

How to convert megawatts to gigawatts and back

01

MW to GW Formula

GW = MW ÷ 1,000

Divide the megawatt value by 1,000 to convert to gigawatts. The conversion factor is 0.001 because one megawatt equals one-thousandth of a gigawatt.

02

GW to MW (Reverse)

MW = GW × 1,000
Example: 2.5 GW × 1,000
Result: 2,500 MW
💡 The SI prefix ladder: W → kW → MW → GW — each step is × 1,000

MW to GW Quick Reference Table

Megawatts (MW)Gigawatts (GW)
100 MW0.1 GW
250 MW0.25 GW
500 MW0.5 GW
750 MW0.75 GW
1,000 MW1 GW
1,200 MW1.2 GW
1,400 MW1.4 GW
1,600 MW1.6 GW
2,000 MW2 GW
2,500 MW2.5 GW
3,000 MW3 GW
5,000 MW5 GW
10,000 MW10 GW
14,000 MW14 GW
22,500 MW22.5 GW

Frequently Asked Questions

How many megawatts are in a gigawatt?

There are exactly 1,000 megawatts (MW) in one gigawatt (GW). The prefix "giga" represents 10⁹ (one billion), while "mega" represents 10⁶ (one million). Dividing 10⁹ by 10⁶ gives 10³ = 1,000. So 1 GW = 1,000 MW = 1,000,000 kW = 1,000,000,000 W.

What is a gigawatt used for?

Gigawatts are used to measure the capacity of national and regional electrical grids, the output of large power plant complexes, and the total installed capacity of entire renewable energy fleets. For example, the total installed electricity generation capacity of the United States is approximately 1,300 GW, and individual nuclear power stations often have 2–4 GW of total capacity.

How much power is 1.21 gigawatts?

The famous 1.21 gigawatts (GW) from "Back to the Future" equals 1,210 MW or 1,210,000 kW. For context, this is roughly the output of one large nuclear reactor (typical reactors produce 0.9–1.6 GW). The Three Gorges Dam in China can produce up to 22.5 GW — about 18.6 times the fictional flux capacitor requirement.

What is the world's largest power plant in GW?

The Three Gorges Dam in Hubei, China is the world's largest power plant at 22.5 GW (22,500 MW) of installed hydroelectric capacity. It has 32 main turbines plus 2 smaller generators. The Itaipu Dam on the Brazil-Paraguay border is second at 14 GW.

How do you convert MW to GW?

To convert megawatts (MW) to gigawatts (GW), divide the megawatt value by 1,000. The formula is: GW = MW ÷ 1,000. For example, 2,500 MW ÷ 1,000 = 2.5 GW. To convert back from GW to MW, multiply by 1,000.

How many homes does 1 GW power?

One gigawatt (1 GW = 1,000 MW) can power approximately 750,000 to 1,000,000 average American homes at any given moment. On an annual energy basis, a 1 GW nuclear plant (with ~90% capacity factor) provides enough electricity for about 700,000–800,000 homes.