Airsoft Ballistics Calculator
Enter BB weight and muzzle velocity to get energy, range and trajectory.
Results
Please enter a valid weight and velocity.
Trajectory (distance vs height)
Weight Comparison (same energy)
Equivalent performance per BB weight at the same muzzle energy.
| Weight | Velocity | Max Range | Effective | Impact Energy |
|---|
What this calculator does
Enter your BB weight (g) and muzzle velocity (FPS or m/s) to get the muzzle energy in joules, plus a numerical simulation with air drag and hop-up (Magnus effect) that estimates max range, effective range, flight time and the full trajectory. It also compares equivalent velocity and range across BB weights at the same energy — handy when choosing BB weight from chronograph readings. See how to read the results.
Frequently Asked Questions
How many FPS is 1 joule with a 0.20g BB?
About 328 fps (100 m/s). Energy is E = ½mv², so 0.20g at 328 fps equals 1.00 J. With 0.25g the same energy gives about 293 fps.
Do heavier BBs make my gun weaker?
No. Your gun delivers nearly the same energy regardless of BB weight — heavier BBs just fly slower (v₂ = v₁·√(m₁/m₂)). They actually retain more energy downrange and resist wind better.
What does "effective range" mean in this calculator?
The distance over which the BB stays within ±25 cm of the launch line — roughly how far you can hit a torso-sized target without adjusting your aim. Max range is simply where the BB lands.
How accurate are these results?
The simulation models air drag and hop-up (Magnus lift) with RK4 numerical integration, using physics constants for a 6mm BB. Real results vary with BB quality, wind and hop rubber condition, so treat them as estimates — they are most reliable for comparing setups.