How many joules does a slingshot have?

Kinetic energy clearly tells you how much power is actually behind your shot. It is given in Joules (J) and is calculated using the formula:
E = 0.5 × m × v²

This means: you take the weight of your projectile in kilograms (e.g., 2.09 g = 0.00209 kg), multiply it by the velocity (e.g., 100 m/s) squared, and then take half of that value.

Example calculation:
• m = 0.00209 kg (corresponds to 2.09 g for an 8 mm steel ball)
• v = 100 m/s
→ E = 0.5 × 0.00209 × 100² = 10.45 Joules

For clay balls (e.g., 0.75 g), the energy at the same velocity is only about 3.75 Joules. This is less penetrating power, but often sufficient – depending on the intended use.

With the following calculator, you can precisely determine your values. Simply enter two of the three known values – the third will be calculated automatically.