18 free tools for UK airsoft players. Convert fps to joules, pick the right BB weight, check your battery, choose your first gun and camo, price up a loadout, pack for game day and find out when you can get UKARA. All of them work on your phone.
Power, chrono & BBs
Understand your chrono reading and get the most out of every BB.
FPS to Joules Calculator
Convert airsoft fps to joules (and back) for any BB weight, then check it against typical UK site limits.
Open the calculator →BB Weight FPS Calculator
Chrono’d on 0.20g? See what your gun shoots with 0.25g, 0.28g, 0.30g and heavier BBs.
Open the calculator →Airsoft Range & BB Weight Calculator
Find the best BB weight for your gun’s power and how far it should reach with a good hop-up.
Open the calculator →Airsoft BB Calculator
How many BBs are in a bag, how many mags it fills, how many game days it lasts and the cost per shot.
Open the calculator →Chrono String Analyser
Paste a string of chrono readings to see your average, highest shot, spread and how consistent your gun is.
Analyse your chrono →Airsoft Spring FPS Calculator
See the typical fps an M90 to M190 spring gives in an AEG or sniper, and which spring hits your site limit.
Open the calculator →Batteries, gas & performance
Power your gun properly and know what an upgrade will do.
Airsoft Battery Calculator
LiPo, LiFePO4 and NiMH voltages, C rating, charge time, storage voltage and a rough shots-per-charge figure.
Open the calculator →Airsoft ROF Calculator
Estimate your AEG’s rate of fire from its gear ratio, motor speed and battery voltage.
Open the calculator →Airsoft Inner Barrel & Hop-up Guide
Match your cylinder to your inner barrel length, and pick the right bore, hop-up rubber and BB weight.
Check your set-up →Airsoft Gas Usage Calculator
How many shots you get from a can of green gas or a box of CO2, and what each shot and game day costs.
Open the calculator →Kit & planning
Choose, budget for and pack the right kit.
Which Airsoft Gun Should I Buy?
Six quick questions to find out whether an AEG, gas, spring or HPA gun suits you best.
Take the quiz →Airsoft Loadout Cost Calculator
Price up a beginner, mid-range or high-end loadout item by item, and see when owning beats hiring.
Build your loadout →Airsoft Camo Picker
Tell us where and when you play, and get the camouflage patterns that will work best.
Find your camo →Airsoft Game Day Checklist
A packing list built for your game: woodland, CQB or milsim, hire or own kit, whatever the weather.
Make your checklist →Airsoft Callsign Generator
Find a callsign that sounds good on the radio: military, animal, tech or funny, with your NATO initials.
Generate a callsign →Airsoft Clothing & Boot Size Converter
Convert boot sizes between UK, EU, US and Mondopoint, and find your clothing, NATO and glove sizes.
Convert your size →Milsim Pack Weight Planner
Add up everything you’ll wear and carry at a milsim, compare it with your body weight and see where to cut.
Plan your pack →UK airsoft law
Work out when you can buy a RIF.
Why fps, joules and BB weight matter
Every UK site chronos your gun before you play, and each one sets power limits for rifles, DMRs and snipers. Those limits are usually given as fps with a 0.20g BB, or in joules. Because fps changes with BB weight, it pays to understand the energy behind the number before you swap BBs or upgrade your gun. Start with the fps to joules calculator, then read our guide to UK airsoft law and BBs explained.
New to airsoft?
Start with the which airsoft gun quiz to find the right type of gun, price your kit with the Airsoft Loadout Cost Calculator, then use the Airsoft Game Day Checklist so you don’t forget anything on the day. When you’re ready to buy a realistic gun, the UKARA Eligibility Checker shows when you’ll qualify.
Frequently asked questions
Are these airsoft tools free?
Yes, all 18 of our airsoft tools are free to use, with no sign-up. They work on your phone, so you can use them at the chrono or while packing your kit bag.
Are the results exact?
The fps, joules, BB weight and BB count calculators use exact formulas. Range, battery shot counts and rate of fire are estimates, because they depend on your gun’s internals and set-up. Your site’s chrono reading is always the one that counts.
What fps is legal for airsoft in the UK?
In UK law an airsoft gun fires at no more than 1.3 joules for single-shot guns or 2.5 joules for guns capable of automatic fire. Most sites set lower limits, commonly 350 fps on a 0.20g BB (1.14 joules) for full-auto rifles, with higher limits for DMRs and snipers. Check any gun with our fps to joules calculator.
Can you suggest a tool?
Yes please. If there’s a calculator or checker that would help your game, tell us about it and we’ll look at adding it.
New to airsoft?
Our beginner guides cover kit, costs, the law and your first game day.
Results are estimates for guidance. Always follow your site’s chrono and safety rules, and your gun maker’s advice.