Free Fall Time Calculator
Fall time and impact speed from height.
Enter your values
Enter the drop height in m.
Enter the initial velocity in m/s, down positive.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Fall time
- 2.02 s
- Impact speed
- 19.81 m/s
- Impact speed
- 71.3 km/h
- Impact speed
- 44.3 mph
Quick answer
Fall time = sqrt(2h/g); impact speed = g x t.
t = sqrt(2h/g)
At a glance
| What it does | Fall time and impact speed from height. |
|---|---|
| Category | Physics |
| Inputs needed | Drop height, Initial velocity |
| Main output | Fall time |
| Formula | t = sqrt(2h/g) |
| Cost | Free — no sign-up, no download |
How to use the Free Fall Time Calculator
- 1Enter the drop height in metres.
- 2Add an initial downward velocity if the object was already moving.
- 3Read the fall time and impact speed.
Inputs explained
- Drop height(m)
- Enter the drop height in m.
- Initial velocity(m/s, down positive)
- Enter the initial velocity in m/s, down positive.
Worked example
Using the values the calculator loads with:
Inputs
- Drop height20 m
- Initial velocity0 m/s, down positive
Results
- Fall time2.02 s
- Impact speed19.81 m/s
- Impact speed71.3 km/h
- Impact speed44.3 mph
Frequently asked questions
Does mass affect fall time?
No — in a vacuum all objects fall at the same rate regardless of mass.
What about air resistance?
Light or wide objects like paper fall slower than this ideal model predicts.
What do I need to enter into the Free Fall Time Calculator?
Just 2 values: drop height, initial velocity. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Free Fall Time Calculator work out the answer?
Fall time = sqrt(2h/g); impact speed = g x t. It applies the formula t = sqrt(2h/g) and shows the working so you can check each step by hand.
Is the Free Fall Time Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.