How to calculate the joules of an air rifle?

When looking for an air rifle, it is common to come across specifications such as velocity in feet per second (FPS), metres per second (m/s) or power in joules (J).

But after all… how can you calculate the joules of an air gun?

And more importantly: why is this value so relevant when choosing the ideal air rifle? In this article, we explain the process step by step so you will never have doubts again.

What are Joules in an air rifle?

The joule (J) is the unit used to measure energy.
In the context of air rifles, it represents the kinetic energy of the pellet as it leaves the barrel.
In other words: more joules = more impact on the target. However, this does not necessarily mean greater accuracy.

That is why it is so important to understand how this value is obtained.

The formula to calculate joules

The kinetic energy of a projectile is calculated using the following formula:

Energy (J) = 1/2 × m × v²

Where:
m = pellet mass (in kg)
v = pellet velocity at the muzzle (in m/s)

Let’s look at a practical example. Suppose we have:

A 0.55 g pellet (0.00055 kg) travelling at a velocity of 240 m/s. Applying the formula:

E = 1/2 × 0.00055 × (240²)

E = 0.000275 × 57,600 ≈ 15.84 J

The air rifle would have approximately 16 joules of real power.

Would you like to explore this topic further? Read our blog article on how to measure the power of an air rifle.

Why is it so important to know the power of an air rifle?

• To ensure legal use: knowing the power helps confirm that the air rifle is within legal limits. Even when purchased from a specialised store, understanding this value helps avoid issues in different situations.
• To compare models before buying: power is a key factor when evaluating different air rifles, helping you choose the one that best suits your needs.
• To diagnose performance issues: if the air rifle is not performing as expected, knowing the actual power can help identify faults or the need for adjustments.
• To monitor wear and performance over time: like any piece of equipment, an air rifle can lose power with use and age. Periodic measurement helps decide when to service or replace it.

Tips for calculating joules accurately

1. Make sure to use the correct units of measurement, namely kilograms for mass and metres per second for velocity;
2. Always check the technical specifications provided by the manufacturer, as they can give a reliable indication of your air rifle’s power;
3. Use a chronograph to accurately measure the pellet’s muzzle velocity;
4. Remember that the joule calculation does not take into account factors such as accuracy or range. It is purely a measure of the air rifle’s power.

More than just an essential element for responsible ownership of an air rifle, understanding joules is also an interesting challenge for any enthusiast who wants to fully understand the performance of their equipment.

At the official store, you will find air rifles across all power categories and suitable for different budgets. Each product description clearly states the power in Joules and/or FPS, making it easy to compare different models and choose the ideal option.

Questions about power, performance or legislation? Our team is always ready to help. Simply contact us via email at [email protected]