Calculates the constant speed a falling object eventually reaches once air resistance balances gravity.
How it works
The object’s weight is balanced against the drag equation, giving the speed at which drag force exactly equals gravitational force.
What this does not include
This does not include the time or distance needed to actually reach terminal velocity — this calculator computes only the final, constant speed itself.
How to use this calculator
- Enter the object’s mass, the fluid’s density, its cross-sectional area, and its drag coefficient.
A worked example
An 80 kg skydiver, air density 1.225 kg/m³, 0.7 m² surface area, drag coefficient 1.0: terminal velocity = 42.7763 m/s — about 154 km/h.
A 1 kg object with a much smaller 0.01 m² area and drag coefficient 0.5: terminal velocity = 56.5877 m/s — a lighter object but a much higher terminal velocity, since its smaller area offers far less air resistance relative to its weight.
What the variables mean
| Variable | Meaning |
|---|---|
| Mass | Falling object’s mass |
| Air density | Density of the air being fallen through |
| Area | Cross-sectional area facing the airflow |
| Drag coefficient | How aerodynamic the shape is |
Edge cases worth knowing
A smaller cross-sectional area relative to mass means a higher terminal velocity — the second example’s dense, small object falls faster than the first’s larger, more air-resistant skydiver shape, despite being far lighter.
Zero air density makes terminal velocity infinite — a vacuum offers no drag to balance gravity, so there’s no speed at which the forces equalize, and the calculator declines to show a result.
Frequently asked questions
Why does a skydiver reach a maximum falling speed?
As speed increases, air resistance (drag) grows until it exactly balances gravity — at that point, acceleration stops and the skydiver falls at a constant speed.
How does body position affect a skydiver’s terminal velocity?
Spreading out increases cross-sectional area and drag coefficient, both of which lower terminal velocity — that’s why a “belly-down” position falls slower than a head-down dive.
Does this apply to falling through any fluid, not just air?
Yes — the same balance-of-forces principle applies to any fluid, using that fluid’s density in place of air’s.
