Terminal Velocity Calculator
Calculate the maximum falling speed (terminal velocity) of an object when air resistance balances gravity.
How to use the calculator
- Enter the mass of the falling object.
- Enter the drag coefficient (Cd) and cross-sectional area — these depend on the object's shape and orientation.
- Standard air density at sea level (1.225 kg/m³) is pre-filled, but can be adjusted for altitude or temperature.
How is it calculated?
Terminal velocity is the speed at which air resistance equals the force of gravity, so the object stops accelerating and falls at a constant speed. A skydiver in a belly-to-earth position typically has a Cd around 1.0 and a cross-sectional area of 0.6–0.9 m², while a curled-up head-down dive position reduces both and results in a higher terminal velocity.
Frequently asked questions
What's a typical Cd value for a person?
A person in belly-to-earth position (arms and legs extended) typically has a Cd around 0.8–1.3, while a curled-up "head-down" dive position can have Cd as low as 0.5–0.7, resulting in higher terminal velocity.
Why is air density adjustable?
Air density decreases with altitude and increases with lower temperature — both affect terminal velocity. The default value of 1.225 kg/m³ applies at sea level and 15°C (59°F).
Does the formula apply to all objects?
The formula is a simplified model that works well for most practical purposes, but extremely small or light objects (like dust particles) are affected more by other effects not captured here.