# Free Fall Calculator

URL: https://speedycalculator.com/calculators/physics/free-fall/
Last updated: 2026-10-25

> The free fall calculator finds how long an object takes to fall from a height and how fast it is moving on impact, ignoring air resistance. Type a fall time to solve for height.

## Inputs

- Height (m, cm, mm, km, in, ft, yd, mi)
- Gravitational acceleration (m/s², ft/s², g)

## Results

- Fall time
- Impact speed

## Formula

```
t = √(2h ÷ g)
v = √(2gh)
```

## Explanation

Without air resistance, all objects fall with the same acceleration regardless of mass, as Galileo showed.

### How to use the Free Fall Calculator

- **Height**
- **Gravitational acceleration**
- Want to work backwards? Type a value into **Fall time** and **Height** is calculated for you.

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Rearranging the equations of motion for constant acceleration gives the time and impact speed.

### Inputs explained

FieldWhat to enterHeightUnits: m, cm, mm, km, in, ft …Gravitational accelerationUnits: m/s², ft/s², g

### What each result means

- **Fall time** = sqrt(2×[Height]÷[Gravitational acceleration])
- **Impact speed** = sqrt(2×[Gravitational acceleration]×[Height])

### Example values

How the main result changes when **Height** changes and everything else stays at the example values above:

Height (m)Fall time (s)101.428151.749202.02252.258302.474402.856

## Worked example

Inputs — Height: 20 m; Gravitational acceleration: 9.80665 m/s².

Results — **Fall time = 2.02 s**; Impact speed = 19.81 m/s.

## FAQ

**Does air resistance matter?**
For heavy compact objects over short drops, little; for feathers or long falls, a lot.

**What is terminal velocity?**
The speed where drag equals weight, about 55 m/s for a skydiver belly-down.

**What formula does the Free Fall Calculator use?**
t = √(2h ÷ g).

**Can I work backwards from the result?**
Yes. Type the result you want into Fall time and the calculator finds the matching height.


## Sources

- [NIST – Fundamental physical constants](https://physics.nist.gov/cuu/Constants/)