Escape Velocity Calculator

How it works

1. 1Select a preset body (Earth, Moon, Mars, Jupiter, or Sun) or choose Custom to enter your own mass M (kg) and radius r (m).
2. 2The calculator applies the escape-velocity formula v = √(2GM ÷ r), where G = 6.6743×10⁻¹¹ N·m²/kg².
3. 3Results are shown in m/s, km/s, and km/h so you can compare with spacecraft speeds and mission data.

Use cases

• Aerospace students verifying mission Δv budgets for planetary departure burns.
• Educators showing how surface gravity and planet size affect the energy needed to leave.
• Curious readers checking whether sci-fi ship speeds are realistic for different bodies.

Frequently asked questions

What is the escape velocity formula?

v = √(2GM ÷ r), where G = 6.6743×10⁻¹¹ N·m²/kg², M is the body’s mass in kg, and r is its radius in metres. For Earth (M ≈ 5.972×10²⁴ kg, r ≈ 6.371×10⁶ m) this gives v ≈ 11,186 m/s ≈ 11.2 km/s.

Does the mass of the escaping object matter?

No. The formula contains only the central body’s mass M and radius r — the mass of the rocket or projectile cancels out. A feather and a spaceship need the same launch speed to escape the same planet (ignoring air resistance).

Why is Earth’s escape velocity about 11.2 km/s?

Plugging Earth’s mass and mean radius into v = √(2GM ÷ r) gives ≈ 11,186 m/s. This is the minimum speed an object at the surface needs (ignoring atmospheric drag) to escape Earth’s gravity without further propulsion.