Terminal Velocity Calculator

How to Use This Calculator

1. Enter object mass in kg.
2. Enter cross-sectional area perpendicular to motion (m²).
3. Select or enter drag coefficient Cd.
4. Set fluid density (air at sea level = 1.225 kg/m³).
5. Results show terminal velocity in m/s, mph, and km/h. Use Extended tabs for skydiver cases and other fluids.

Formula

Example

Frequently Asked Questions

• What is terminal velocity? ▼
  Terminal velocity is the constant speed reached when drag force equals gravitational force, giving zero net acceleration. An object stops accelerating when F_drag = mg. Formula: Vt = √(2mg / ρCdA).
• What is a skydiver's terminal velocity? ▼
  In belly-to-earth position (Cd≈1.0, A≈0.7 m²), a 80 kg skydiver reaches about 120 mph (54 m/s). Head-down (Cd≈0.7, A≈0.3 m²) gives about 200 mph. With an open parachute (Cd≈1.5, A≈40 m²), terminal velocity drops to about 15–20 mph.
• What drag coefficient should I use? ▼
  Common values: sphere 0.47, flat disk 1.17, streamlined body 0.04, human belly-to-earth ~1.0, human head-down ~0.7, open parachute ~1.3–1.5. The value depends on shape and Reynolds number.
• How long does it take to reach terminal velocity? ▼
  The time constant τ = Vt/g. An object reaches ~95% of terminal velocity after about 5τ. For a skydiver at 54 m/s, τ ≈ 5.5 s, so 95% Vt is reached in about 27 seconds of freefall (~700 m).
• How does altitude affect terminal velocity? ▼
  Air density decreases with altitude. At 10,000 m, ρ ≈ 0.414 kg/m³ vs 1.225 at sea level. Since Vt ∝ 1/√ρ, terminal velocity at 10,000 m is about 72% higher than at sea level.

Related Calculators