🪂 Free Fall Calculator
Solve free fall from rest: enter a drop height, time or impact speed and get the others, with gravity you can change for the Moon or Mars.
Impact speed v
29.7086 m/s
Free fall from rest: v = gt, h = ½gt², v = √(2gh). g = 9.80665 m/s² on Earth (editable). 🔒 Computed in your browser.
How the free fall calculator works
An object dropped from rest accelerates at g. The equations are v = gt, h = ½gt², and v = √(2gh). Enter any one of height, time or impact speed (with g, default 9.80665 m/s²) and the tool solves the rest.
Distinct “drop height / fall time / impact speed” intent. Change g to model the Moon (1.62) or Mars (3.72). Ignores air resistance, so real objects hit a terminal velocity and land slower.
Frequently asked questions
How do I calculate the time to fall a given height?
From h = ½gt², t = √(2h/g). Dropping 45 m on Earth takes √(90/9.8) ≈ 3.03 s. Enter the height and the tool computes the time.
How fast is something going when it lands?
v = √(2gh), or v = gt. From 45 m, v ≈ 29.7 m/s (ignoring air resistance). Enter height or time to get the impact speed.
Does free fall depend on mass?
No — in the absence of air resistance, all objects fall at the same rate. A feather and a hammer land together in a vacuum.
What is g?
The acceleration due to gravity: about 9.80665 m/s² on Earth. It differs elsewhere — 1.62 on the Moon, 3.72 on Mars — which you can select.
Why is my real-world answer different?
Air resistance slows real falls and caps them at a terminal velocity, so actual impact speeds are lower than the ideal free-fall value for light or slow objects.