Calculate the escape velocity needed to break free from any planet or celestial body's gravity. Enter the mass and radius of the body, and get back the escape velocity in km/s, m/s, and mph — plus the first cosmic velocity (orbital speed). Works for Earth, Mars, the Moon, or any custom world you define.
Escape Velocity
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Escape Velocity (m/s)
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Escape Velocity (mph)
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First Cosmic Velocity (Orbital Speed)
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Surface Gravity
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Escape velocity is the minimum speed an object must reach to break free from a celestial body's gravitational pull without any additional propulsion. Once an object reaches this speed, it can travel away indefinitely, overcoming gravity's pull. Importantly, this speed is independent of the mass or shape of the escaping object — only the planet's mass and radius matter.
Escape velocity is calculated using the formula Vₑ = √(2GM/R), where G is the gravitational constant (6.674 × 10⁻¹¹ N·m²/kg²), M is the mass of the celestial body in kilograms, and R is its radius in meters. The result is the escape speed in meters per second, which you can convert to km/s by dividing by 1000.
Earth's escape velocity is approximately 11.186 km/s (about 6.95 miles per second or roughly 25,000 mph). This is the speed a rocket must achieve to leave Earth's gravitational field entirely and travel into deep space without further thrust.
Earth's escape velocity of ~11.186 km/s converts to approximately 25,020 mph (miles per hour). For context, a commercial airplane flies at around 575 mph — so escape velocity is about 43 times faster than a typical jetliner.
The first cosmic velocity is the minimum orbital speed needed to maintain a circular orbit just above a planet's surface without any thrust. It is calculated as V₁ = √(GM/R), which equals the escape velocity divided by √2. For Earth, this is approximately 7.91 km/s. The escape velocity (second cosmic velocity) is always √2 ≈ 1.414 times greater than the first cosmic velocity.
No — escape velocity is a scalar (speed), not a vector. The direction of travel does not affect the minimum speed required to escape. However, in practice, launching in the direction of Earth's rotation gives rockets a helpful velocity boost, reducing the fuel needed to reach escape velocity.
The Moon's escape velocity is about 2.38 km/s (~5,323 mph), which is much lower than Earth's because the Moon is far less massive. This is why Apollo missions required far less fuel to lift off from the Moon's surface than to launch from Earth.
No — a black hole is defined as an object whose escape velocity exceeds the speed of light (299,792 km/s). The boundary at which escape velocity equals the speed of light is called the Schwarzschild radius or event horizon. Beyond this point, not even light can escape, making the region invisible and undetectable by conventional means.