Earth
The only home we have ever known.
How big is Earth? Earth is 12,756 km (7,926 miles) across at the equator, the largest of the four rocky planets. Its surface gravity is 9.8 m/s² and it orbits the Sun at an average 149.6 million km (1 AU).
Liquid water, a protective atmosphere, and a living surface make Earth a remarkable place. Its tilted axis gives us seasons as we travel around the Sun.
Image: NASA / Apollo 17 crew. Processed mission imagery; apparent color varies with filters and processing.
Earth quick facts
| Planet type | Terrestrial planet |
|---|---|
| Equatorial diameter | 12,756 km (7,926 mi) |
| Mean radius | 6,371 km (3,959 mi) |
| Equatorial circumference | 40,074 km (24,901 mi) |
| Surface area | 5.10 × 10⁸ km² |
| Volume | 1.08 × 10¹² km³ |
| Mass | 5.97 × 10²⁴ kg (1 Earth masses) |
| Mean density | 5,514 kg/m³ (5.51 g/cm³) — the densest planet |
| Surface gravity | 9.8 m/s² (1× Earth) |
| Escape velocity | 11.2 km/s |
| Length of day (solar) | 24 hours |
| Rotation period (sidereal) | 23.9 hours |
| Orbital period (year) | 365.2 Earth days (1 Earth years) |
| Mean distance from the Sun | 149.6 million km (93 million mi) · 1 AU |
| Closest and farthest from the Sun | 147.1 – 152.1 million km |
| Sunlight travel time | 8.3 minutes |
| Mean orbital speed | 29.8 km/s |
| Axial tilt | 23.4° |
| Mean temperature | 15 °C |
| Known moons | 1 |
| Ring system | No |
Reference: NASA Planetary Fact Sheet. Rounded values; diameters are equatorial, area and volume use the mean radius. Moon counts include discoveries announced through 2025 (such as Uranus’s S/2025 U1) and keep growing as new moons are confirmed.
How big is Earth?
Earth is 12,756 km (7,926 miles) wide at the equator and slightly narrower pole to pole. It is the largest and densest of the rocky planets, but Jupiter is 11.2 times wider and about 1,321 Earths could fit inside it.
The Moon, 3,475 km across, is about 27% of Earth’s width. See every planet to scale ↗
What is the gravity on Earth?
Surface gravity on Earth averages about 9.8 m/s², the reference value for “1 g”. Escape velocity is 11.2 km/s.
Calculate your weight on Earth ↗How far is Earth from the Sun?
Earth orbits an average 149.6 million km (93 million miles, 1 AU) from the Sun, ranging from 147.1 to 152.1 million km. Sunlight takes 8.3 minutes to get there.
Time sunlight’s journey ↗How long is a day and a year on Earth?
A solar day on Earth lasts 24 hours, and one spin relative to the stars takes 23.9 hours. A year — one trip around the Sun at 29.8 km/s — lasts 365.2 Earth days (1 Earth years). Its axis is tilted 23.4°.
Watch the orbit ↗Is Earth a rocky planet or a gas giant?
No. Earth is a terrestrial, or rocky, planet with a solid surface of rock and metal — one of the four inner planets with Mercury, Venus, Earth and Mars. The gas giants are Jupiter and Saturn.
Meet all eight planets ↗Earth questions, answered
How big is Earth?
Earth is 12,756 km (7,926 miles) wide at the equator, with a mean radius of 6,371 km. Its equatorial circumference is about 40,074 km (24,901 miles) and its surface area about 510 million km².
What is the gravity on Earth?
Surface gravity averages about 9.8 m/s² (standard gravity is defined as 9.80665 m/s²). It is slightly weaker at the equator than at the poles because Earth spins and bulges.
What is Earth’s mass?
About 5.97 × 10²⁴ kg. Jupiter is 318 times as massive, while Mars has about 0.11 of Earth’s mass.
How far is Earth from the Sun?
On average 149.6 million km (93 million miles), defined as about 1 AU. Earth is closest, 147.1 million km, in early January and farthest, 152.1 million km, in early July. Sunlight takes about 8.3 minutes to arrive.
How long is a day and a year on Earth?
A solar day lasts 24 hours, while one rotation relative to the stars takes about 23.9 hours. One orbit around the Sun takes 365.2 days.
Is Earth a rocky planet or a gas giant?
No. Earth is a terrestrial, or rocky, planet with a solid surface of rock and metal — one of the four inner planets with Mercury, Venus, Earth and Mars. The gas giants are Jupiter and Saturn.
What is Earth’s density?
Earth’s mean density is 5,514 kg/m³ (5.51 g/cm³) — the densest planet. Its iron-nickel core makes it denser than any other planet.