How Much Pressure Is in a CO2 Cartridge? (2026)
How much pressure is in a CO2 cartridge?
Want a clear number and simple explanation you can use at the range. This article will give a quick answer, a PSI vs temperature chart, and easy-to-follow safety tips.
You will learn why temperature sets the pressure, why cartridges hold liquid and gas, and how pressure changes as you fire. You will also get testing tips, common failure signs, and troubleshooting steps.
All key numbers will be backed by trusted sources and maker specs. Expect a printable quick‑reference, a small diagram, and a short safety checklist to keep your shooting safe and consistent.
How much pressure is in a CO2 cartridge?
At room temperature (~20–21 °C / 68–70 °F) the vapor pressure of CO2 inside a cartridge is roughly 800–900 psi (≈57–62 bar).
Quick PSI reference for common temperatures: 20 °C (68 °F) ≈ 830 psi and 25 °C (77 °F) ≈ 930 psi. At 30 °C (86 °F) pressure rises to about 1,040 psi and at the critical point (31.1 °C / ≈88 °F) it is near 1,070 psi.
If you’re asking how much pressure is in a co2 cartridge at different temperatures, the short answer is: temperature controls the pressure, not the cartridge weight. A full 12 g and an 8 g cartridge at the same temperature will show nearly identical internal pressure; the larger cartridge simply contains more liquid to sustain that pressure longer.
The numbers above reflect saturated vapor pressures from trusted thermophysical data and common cartridge spec sheets. For manufacturer charts and valve specs see the cartridge pressure reference.
Myth check: bigger cartridge = higher pressure is false. Pressure comes from temperature-driven vapor equilibrium; cartridge size only affects duration and total gas available.
How temperature affects CO2 pressure
CO2 follows a clear vapor-pressure vs temperature curve: warmer means higher pressure and colder means lower pressure. A small temperature change can move pressure by hundreds of psi, so temperature control matters on the field.
Between 20 °C and 30 °C the pressure climbs by roughly 200 psi (about 830 → 1,040 psi), which shows why you feel different performance on hot days. Near the critical point at 31.1 °C (≈88 °F) CO2 stops behaving like a simple liquid+vapor mix and its properties change, keeping pressure high and more sensitive to heat.
Practical examples: leaving cartridges in a hot car or direct sun risks pushing pressure higher and stressing seals or the device. Conversely, cold weather reduces pressure and can cut velocity or cause failures; rapid firing also cools the cartridge as liquid vaporizes, temporarily lowering pressure and performance.
Always be cautious about overpressure: manufacturers often warn not to expose disposable cartridges to extreme heat or open flames and provide maximum recommended temperatures in their manuals. When in doubt consult the spec sheet or NIST thermophysical data for exact pressure-vs-temperature numbers.
Why CO2 cartridges contain liquid and gas (and why that matters)
CO2 cartridges hold both liquid and gas in equilibrium so the vapor pressure stays almost constant while liquid remains. That phase equilibrium is why a gun can produce consistent velocities for many shots until the liquid is mostly used.
Because the liquid buffers pressure, you get steady performance and then a sudden falloff when the liquid runs out and the cartridge moves to a gas-only state. That abrupt change explains why guns “fall off a cliff” in FPS rather than gradually fading every shot.
Vaporization requires energy, so rapid discharge cools the cartridge (latent heat effect) and lowers pressure during sustained firing. This cooling can cause temporary velocity drops, so paced shooting often maintains steadier performance than long rapid strings.
Orientation matters: holding a cartridge upside down can allow liquid CO2 to reach the valve, which some setups use to boost output, while other designs expect gas-only feed and can be damaged by liquid. For a visual demo of the physics, check a short pressure explainer video that shows liquid/gas behavior.
How pressure changes during firing: shots, velocity and signs a cartridge is low
Expect wide variation in shot counts: a 12 g CO2 in an airsoft pistol can give anywhere from tens to low hundreds of effective shots depending on blowback design, temperature, and firing cadence. High-blowback pistols use more gas per shot, so they empty cartridges faster than non-blowback or low-consumption designs.
Example chronograph pattern (typical test-style example, results will vary): at 20 °C a fresh 12 g might start near 330 FPS, hold within ±10 FPS for the first 15–30 shots, then slowly drift down before a sharper fall after 70–120 shots as liquid is depleted. Treat this as a guideline rather than a guarantee for your model and always chronograph your own guns for exact numbers.
Typical session behavior is stable pressure while liquid remains, then a drop once liquid is gone, producing a clear velocity fall. Signs a cartridge is low include consistent FPS drop on a chrono, weak or missing blowback, increased misfeeds, audible hissing at the valve, and a noticeably cold cylinder after firing.
If you want to check how much pressure is in a co2 cartridge while troubleshooting, use a chronograph and weigh the cartridge before and after firing to estimate gas loss. An inline CO2 gauge or a spare known-good cartridge helps isolate leaks or worn piercers and seals.
Quick troubleshooting checklist: if performance drops, first check cartridge temperature, then swap to a fresh cartridge to see if the problem follows the gas. Next inspect O-rings and the piercer for damage and apply a drop of silicone oil to seals if allowed by your manual.
Safety tips and best practices for handling CO2 cartridges
Store cartridges cool and out of direct sunlight and never expose them to open flame or extreme heat. Always pierce and seat cartridges inside the intended device and wear eye protection when handling pierced or leaking cartridges.
Handle seals and lubrication correctly: use silicone oil on O-rings as the manual recommends and avoid petroleum products. For model-specific seating, storage, and handling tips see the airsoft CO2 guide.
Dispose of cartridges according to local recycling rules—do not incinerate and do not try to refill disposable cylinders. If a cartridge overheats, leaks excessively, or bulges, move people away, cool the area if safe to do so, and seek professional assistance rather than attempting repairs yourself.
What People Ask Most
How much pressure is in a CO2 cartridge?
A CO2 cartridge contains very high internal pressure and should be handled carefully. Treat it like any other pressurized container and follow safety instructions on the device you are using.
Is it dangerous to hold a CO2 cartridge after it has been punctured?
Yes, a punctured cartridge can release cold gas quickly and may cause frostbite or burn-like injuries. Keep hands and face away from the opening and let the gas vent in a safe direction.
Can I store CO2 cartridges in my car or a hot garage?
It’s best to avoid storing cartridges in places that get very hot because heat increases pressure inside the cartridge. Store them in a cool, dry place out of direct sunlight to reduce risk.
Will a small dent or scratch make a CO2 cartridge unsafe to use?
Minor cosmetic damage might not cause a problem, but deep dents or punctures can weaken the cartridge and create a hazard. If you see obvious damage, replace the cartridge rather than risking use.
Do CO2 cartridges lose pressure over time if they are unopened?
Unopened cartridges can slowly lose a tiny amount of gas over a long time, but most stay usable for a long period. Check the device manufacturer’s storage recommendations for best results.
How can I tell if a CO2 cartridge will work with my inflator or airgun?
Check the device instructions to see what cartridge types and sizes it accepts, and make sure the cartridge fits your tool correctly. Using the wrong cartridge can cause poor performance or safety problems.
Is it safe to try and refill a CO2 cartridge at home?
Refilling cartridges at home is not recommended because it can be dangerous and may damage the cartridge. Use new cartridges or visit a professional refill service if available and approved for your device.
Final Thoughts on CO2 Cartridge Pressure
We opened with a quick answer — at room temp vapor pressure is about 800–900 psi — and even a number like 270 can be a handy bookmark for readers. Understanding how pressure ties to temperature and liquid content gives you steadier performance and easier troubleshooting, so your shots stay consistent and your gear lasts. The core benefit is confidence in how your gas behaves, not guesswork.
One realistic caution: heat raises pressure quickly and can push disposable cartridges toward unsafe limits, while rapid firing cools the can and lowers output. We showed the temperature table, why liquid-plus-gas matters, and how to spot a low cartridge so you’ll notice symptoms before they wreck a session. That practical knowledge keeps play safer and more reliable.
These points help recreational and competitive airsoft players, techs, and anyone who relies on CO2 for steady performance, and they turn that opening quick answer into usable rules of thumb. Keep checking temps and signs, and you’ll be set for smarter, safer shooting sessions ahead.