Airsoft numbers, instantly.

Tools

• FPS to joules calculator

  Muzzle energy from velocity and BB weight, checked against Japan’s 0.98 J legal limit and common field limits.

• BB weight FPS converter

  Convert a chrono reading on 0.20 g BBs to the velocity you’ll get with 0.25 g, 0.28 g and heavier.

• Battery life calculator

  Rough shots per charge and games per battery from capacity, chemistry and motor type.

• Starter kit budget

  Pick a play style and a tier to get a full starter loadout estimate with a breakdown.

• Effective range estimate

  Rough effective range from muzzle energy and BB weight.

• Gear ratio and rate of fire

  Rounds per second from motor speed, battery voltage and gear ratio.

• Unit converter

  FPS and m/s, joules, grains and grams, inches and millimetres.

• Game day cost calculator

  Entry fee, travel, rentals and BBs totalled per person and per day.

• Gas gun temperature chart

  How much a gas gun’s velocity changes with temperature, for HFC134a and green gas.

• Game day checklist

  Tick off your kit before you leave. Printable, and it remembers your ticks.

Guides

• Playing airsoft in Japan as a visitor: how fields work, what it costs, what to bringA practical guide for travellers who want to play airsoft in Japan. How open days work, rentals, the chrono check, etiquette that differs from the US and UK, and what a day costs.
• Japan's airsoft law explained: the 0.98 J limit, where it comes from, and what it means for your gunThe Japanese Firearms and Swords Control Law sets an energy limit for airsoft guns. Here is the actual rule (3.5 J/cm²), how it becomes 0.98 J for 6 mm BBs, the 0.135 J youth standard, and what happens if a gun exceeds it.
• BB weight explained: what changes between 0.20, 0.25 and 0.28 g, and why Japan plays on 0.25How BB weight affects velocity, energy, trajectory and range, with numbers. Which weight to run for AEGs, gas guns and bolt actions, why 0.25 g is the Japanese default, and what joule creep means for your chrono reading.
• Japanese gas guns and HFC134a: why they're built for "duster gas", and what green gas does to themTokyo Marui, KSC and Marushin gas guns are designed around HFC134a, a lower-pressure gas than green gas or propane. What that means for velocity, parts life, Japan's 0.98 J limit, cold weather, and whether you can convert a Japanese gun to green gas.
• LiPo batteries for AEGs: choosing, charging, storing, and what not to do7.4 V vs 11.1 V, reading mAh and C ratings, picking a charger, safe storage voltage, and how to dispose of a puffed pack. A first-LiPo guide for AEG owners, with notes on what Japanese-spec guns can take.

All guides