This free fall calculator finds how long an object takes to fall a given height, how fast it is moving when it lands, or how far it falls in a given time — pure gravity, starting from rest, no air resistance.
The Free Fall Equations
An object dropped from rest under gravity g obeys two linked facts: its velocity grows linearly (v = g × t) and its distance grows quadratically (h = ½ × g × t²). Eliminating t gives the calculator’s main relation: t = √(2h/g) and v = √(2gh). This is the vertical component of every Projectile Motion arc, and the purest case of constant acceleration (see the Acceleration Calculator). Part of our Physics Calculators collection.
Worked Example (Verified)
Drop an object from 20 m (about a 6-story building) on Earth:
- Fall time: √(2 × 20 ÷ 9.81) = 2.02 seconds
- Impact velocity: 9.81 × 2.02 = 19.8 m/s ≈ 71 km/h — highway speed, reached in two seconds with no engine: that is gravity’s quiet power.
- On the Moon the same drop takes 4.97 s and lands at just 8.05 m/s — type g = 1.62 to see it.
Why Everything Falls Together
Notice what is not in the formulas: mass. A hammer and a feather dropped together in a vacuum land together — demonstrated on the Moon by Apollo 15’s David Scott in 1971. On Earth, air resistance hides the truth (feathers flutter), which is why this calculator models the idealized case and light, fluffy objects will fall slower than it predicts. Dense objects over short drops match it closely.
Terminal Velocity — Where Free Fall Ends
In air, drag grows with speed until it balances gravity: the object stops accelerating at its terminal velocity (~53 m/s for a belly-down skydiver, far more head-down, far less for a feather or parachute). This calculator does not model drag; treat its results as exact for vacuum and close for dense objects over modest heights.
Related Tools
- Projectile Motion Calculator — launched, not just dropped
- Acceleration Calculator
- Physics Calculators — the full collection
Frequently Asked Questions
How long does it take to fall 100 meters?
t = √(200/9.81) ≈ 4.52 seconds in a vacuum, landing at ~44.3 m/s (159 km/h). Air resistance stretches this slightly for real objects.
What is the formula for free fall?
h = ½gt² for distance from rest, v = gt for velocity, and combining them v = √(2gh) — velocity from height without knowing time.
Does a heavier object fall faster?
No (without air). Galileo’s insight, Einstein’s equivalence principle, and an Apollo astronaut’s hammer-feather drop all say the same: gravity accelerates every mass identically.
What is terminal velocity?
The speed at which air drag equals gravity’s pull, so acceleration stops. About 53 m/s for a spread-eagled skydiver; a parachute is engineered to cut it to ~5 m/s.
How fast do you fall after 1 second?
9.81 m/s — and you have fallen 4.9 m. After 2 s: 19.6 m/s and 19.6 m fallen. Velocity grows evenly; distance grows with the square.
Is this free fall calculator free?
Yes — free, instant, no sign-up.