Free fall calculator (time and speed)
Work out how long an object takes to fall and how fast it lands. Example: from 20 meters it takes ~2 seconds and ends at roughly 71 km/h.
Ideal model, no air resistance. In reality air slows the fall — a lot for parachutes, little for dense objects and short drops.
How the calculation works
Starting from rest, the fall time is t = √(2h ÷ g) and the impact speed is v = √(2·g·h) = g·t. Mass doesn't matter: in a vacuum a feather and a stone fall together.
Examples
- A 20 m fall: t ≈ 2 s; hits v ≈ 19.8 m/s (~71 km/h).
- Something taking 3 s to fall dropped from h = ½ × 9.8 × 3² ≈ 44 m.
Frequently asked questions
Do heavier objects fall faster?
In a vacuum, no — all accelerate equally. The everyday difference comes from air resistance, not weight.
What about air resistance?
In real falls, air slows the body to a "terminal velocity". The formulas hold for the ideal case or short falls.
What is g?
Earth's gravitational acceleration: ~9.8 m/s². On the Moon it is ~1.6 m/s².
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Updated on June 30, 2026 · by Rafael Rossi · Methodology & sources