Reviewed by: David Chen, CSCS (Certified Strength and Conditioning Specialist)
This calculator uses accepted physics principles (kinematics) to determine jump performance.
The Vertical Jump Calculator uses the universally accepted flight time method (time-in-air) to estimate an athlete’s maximum vertical leap. This method provides accurate results by calculating jump height based on the time spent airborne, or conversely, calculating the required time to achieve a specific height.
Vertical Jump Calculator
Detailed Calculation Steps
Vertical Jump Calculator Formula
The calculation is based on the kinematic equation relating vertical displacement, gravity, and time.
1. Calculating Jump Height ($H$) from Flight Time ($T$):$H_{meters} = \frac{g \times T^2}{8}$
Where $g$ (acceleration due to gravity) is approximately $9.81 m/s^2$.
2. Calculating Flight Time ($T$) from Jump Height ($H$):$T_{seconds} = \sqrt{\frac{H_{meters} \times 8}{g}}$
Variables Explained
- Flight Time ($T$): The total duration (in seconds) that the athlete is airborne. This is typically measured using electronic timing mats or jump sensors.
- Jump Height ($H$): The vertical displacement of the center of mass (measured in centimeters or inches) from the point of take-off to the highest point of the jump.
- Preferred Unit: The unit system (Metric or Imperial) the user wants the final Jump Height result displayed in.
- Gravity ($g$): A constant, $9.81 m/s^2$, representing the acceleration rate of gravity.
Related Calculators
What is the Vertical Jump Calculator?
The Vertical Jump Calculator is a digital tool designed to help athletes, coaches, and fitness enthusiasts quickly and accurately determine vertical jump performance using fundamental physics principles. The ‘flight time’ method is considered one of the most reliable ways to measure vertical jump in a laboratory or gym setting, as it removes the human error associated with manually measuring reach differences (like in the common “Vertec” test).
The calculation relies on the relationship between time and displacement under constant acceleration (gravity). Since the time to jump up equals the time to fall down, and the total flight time is $2 \times t_{up}$, the height can be calculated precisely without needing to measure reach directly. This is a crucial metric for evaluating explosive strength and power, especially in sports like basketball, volleyball, and track and field.
How to Calculate Vertical Jump (Example)
Let’s calculate the Jump Height when the recorded Flight Time is $0.75$ seconds.
- Identify the formula: Since we are solving for Jump Height ($H$) from Flight Time ($T$), we use: $$H_{meters} = \frac{g \times T^2}{8}$$
- Substitute the values: $g = 9.81 m/s^2$ and $T = 0.75$ seconds. $$H_{meters} = \frac{9.81 \times (0.75)^2}{8}$$
- Calculate the squared time: $(0.75)^2 = 0.5625$.
- Perform multiplication: $9.81 \times 0.5625 = 5.518125$.
- Calculate height in meters: $\frac{5.518125}{8} \approx 0.68977$ meters.
- Convert to Centimeters (Metric): $0.68977 \times 100 \approx 68.98 cm$.
A flight time of 0.75 seconds corresponds to a vertical jump of approximately 69.0 cm (or 27.2 inches).
Frequently Asked Questions (FAQ)
- How accurate is the flight time method? The flight time method is highly accurate, often considered the gold standard for non-contact field testing. Its main limitation is the accuracy of the timing device itself, but electronically measured time-in-air is significantly more reliable than manual reach measurements.
- What is a good vertical jump height? A “good” height depends heavily on the sport, age, and sex of the athlete. For male college athletes, a vertical jump over 30 inches (76 cm) is typically considered excellent. For non-athletes, anything over 15 inches (38 cm) is average.
- How does gravity affect the calculation? The value $g = 9.81 m/s^2$ is an essential constant representing the Earth’s gravitational pull. Because gravity is the only force acting on the body during the flight phase, the calculation can precisely determine the height reached regardless of the athlete’s weight.
- Can I use this calculator to find jump height if I only use a tape measure? No. If you use a tape measure and subtract your standing reach from your jump reach (the Vertec test), you already have the jump height. You should enter that height into the calculator to find your corresponding Flight Time.