Choose final speed, height fallen, or fall duration, then enter the two known values and select Calculate. This constant-acceleration model starts from rest; it does not fix the acceleration to Earth’s gravity or assess jump safety.
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Bungee Jump (Free-Fall) Speed Formula
The calculator uses constant acceleration from rest and treats the final speed as twice the average speed during the fall. The two inputs determine the implied acceleration, shown with the result. Ideal free fall near Earth requires about 9.8 m/s²; arbitrary input pairs need not satisfy that condition. The model ignores air resistance, cord stretch, jumper position, and rebound effects.
- v = final speed at the end of the free-fall portion
- h = height fallen during free fall
- t = free-fall duration
If you enter height and time, the calculator finds final speed using v = 2h / t.
If you enter height and final speed, it finds time using t = 2h / v.
If you enter time and final speed, it finds height using h = vt / 2.
All inputs are converted to meters, seconds, and meters per second for the calculation, then converted back to the unit you selected.
Reference Free-Fall Speeds by Height
These values show ideal free-fall from rest near Earth using gravity only. They are useful for checking whether a result is in a reasonable range, but real bungee jumps differ because the cord begins to stretch and air resistance increases with speed.
| Height Fallen | Approx. Time | Final Speed | Final Speed |
|---|---|---|---|
| 10 m | 1.43 s | 14.0 m/s | 31.3 mph |
| 25 m | 2.26 s | 22.1 m/s | 49.5 mph |
| 50 m | 3.19 s | 31.3 m/s | 70.0 mph |
| 75 m | 3.91 s | 38.4 m/s | 85.8 mph |
| 100 m | 4.52 s | 44.3 m/s | 99.0 mph |
Common Unit Conversions
| Quantity | Conversion |
|---|---|
| Height | 1 ft = 0.3048 m |
| Height | 1 yd = 0.9144 m |
| Speed | 1 m/s = 3.6 km/h |
| Speed | 1 m/s = 2.2369 mph |
| Time | 1 min = 60 s |
Example Calculations
Example 1: Find final speed
You fall 50 meters for 3.2 seconds. Find the final speed.
The final speed is 31.25 m/s, which is about 69.9 mph.
Example 2: Find height fallen
In a constant-acceleration example starting from rest, final speed is 25 m/s after 4 seconds. Find the height fallen. These values imply 6.25 m/s², so this is not ideal free fall near Earth.
The height fallen is 50 meters.
FAQ
Does this calculate the full bungee jump?
No. It relates height, time, and final speed for a constant-acceleration fall from rest. It represents ideal free fall near Earth only when the implied acceleration is about 9.8 m/s². A full bungee jump also depends on cord length, cord stiffness, jumper mass, harness position, damping, and safety limits. Do not use this calculator to plan or judge jump safety.
Why does the calculator ask for any 2 values?
Select the value to solve for, then enter the other two positive values. The formulas connect height, time, and final speed for constant acceleration from rest without fixing that acceleration. If Earth’s gravity were fixed as an additional assumption, these quantities would no longer be independent.
Does this include air resistance?
No. Air resistance is ignored. At higher speeds, air resistance can reduce the actual speed compared with a simple ideal free-fall calculation.
