Calculate cliff jump height or fall time from one known value, converting between seconds or minutes and meters or feet using gravity.
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Cliff Jump Height Formula
The cliff jump height calculation uses the basic free-fall equations for an object starting from rest. It assumes gravity is constant at 9.81 m/s2 and ignores air resistance.
- h = cliff height or vertical drop distance
- t = fall time
- g = acceleration due to gravity, 9.81 m/s2
If you enter the fall time, the calculator solves for height using h = (g*t²)/2. If you enter the height, it solves for fall time using t = sqrt((2*h)/g). Time values are converted to seconds before calculation, and height values are converted to meters before calculation. The result is then converted back into the unit you selected.
Common Cliff Jump Fall Times
These values use the same free-fall assumption as the calculator: starting from rest, no air resistance, and gravity equal to 9.81 m/s2.
| Height | Height | Fall Time |
|---|---|---|
| 5 m | 16.4 ft | 1.01 s |
| 10 m | 32.8 ft | 1.43 s |
| 20 m | 65.6 ft | 2.02 s |
| 30 m | 98.4 ft | 2.47 s |
Unit Conversions Used
| Unit | Conversion |
|---|---|
| 1 minute | 60 seconds |
| 1 foot | 0.3048 meters |
| 1 meter | 3.28084 feet |
Cliff Jump Height Examples
Example 1: Find height from fall time
You measured a fall time of 2 seconds.
The cliff height is about 19.62 meters, or about 64.37 feet.
Example 2: Find time from height
You enter a height of 50 feet. First convert feet to meters.
The fall time is about 1.76 seconds.
Cliff Jump Height Calculator FAQ
Does this calculator tell me if a cliff jump is safe?
No. It only calculates height or fall time using a physics formula. It does not account for water depth, submerged rocks, body position, currents, wind, takeoff angle, or landing conditions. Those factors matter for safety but are outside this calculation.
Why does the formula use 9.81 m/s2?
9.81 m/s2 is the standard acceleration due to gravity near Earth’s surface. That means your downward speed increases by about 9.81 meters per second every second during free fall, ignoring air resistance.
Why do I need to enter exactly one value?
The calculator solves for the missing variable. If you enter height, it calculates time. If you enter time, it calculates height. If both fields are filled or both are blank, there is no single missing value to solve for.
