Where to refill CO2 tanks depends on what you use them for
CO2 tanks get refilled at welding supply shops, paintball retailers, aquarium stores, and some sporting goods stores — but which one works for you depends on the tank size and what you're using it for. A welding supply company will refill almost any tank but may charge a deposit if you don't own it. A paintball shop handles smaller tanks quickly. An aquarium store works if you have a planted tank setup. The fastest option is usually whoever sold you the tank originally, since they already have your tank type on file.
The process itself is straightforward: you bring the tank in, they weigh it to confirm it's empty or nearly empty, they refill it from their bulk supply, and you pay by weight or by refill. Most places charge between $15 and $30 per refill, though prices vary by location and tank size. Some shops offer tank exchanges instead — you trade your empty tank for a full one and pay a flat fee, which is faster but slightly more expensive over time.
Key Takeaways
- Welding supply shops refill the widest range of tank sizes and types, but you may need to pay a deposit if you don't own the tank.
- Paintball retailers specialize in small tanks and offer quick refills, usually while you wait.
- Aquarium stores refill CO2 systems for planted tanks and often know the specific regulators and fittings you need.
- Tank exchanges let you swap an empty tank for a full one when ready, but cost more per refill than traditional refilling.
- Calling ahead saves time — not all shops refill every day, and some require appointments for larger tanks.
Welding supply companies handle the most tank types
A welding supply shop is the most reliable option if you have a standard CO2 tank of any size. These shops refill tanks for welding, cutting, and industrial use, so they have the equipment and informed for tanks ranging from small cylinders to large industrial bottles. They typically charge by the pound of CO2 you receive, so a 5-pound tank costs less to refill than a 20-pound tank.
The catch is that many welding suppliers require you to own the tank or pay a deposit. If you show up with a tank you borrowed or inherited, they may ask for $20 to $50 as a deposit until you return it. Some shops will refill borrowed tanks without a deposit if you have ID and a credit card on file. Call ahead and ask about their policy — it varies by location.
Welding supply shops are also the best choice if you need your tank refilled on a specific day. Most are open during business hours only, and some require 24 hours' notice for larger tanks. Smaller tanks (under 10 pounds) usually refill while you wait.
Paintball shops specialize in quick refills for small tanks
If you have a paintball marker or airsoft gun, a paintball retailer is your fastest option. These shops refill small CO2 cartridges and tanks constantly, so the process takes minutes. Many paintball shops will refill your tank while you browse, and some offer same-day service even without an appointment.
Paintball retailers typically charge a flat fee per refill rather than by weight — usually $5 to $10 for a small tank. This makes the cost predictable, though you pay more per pound of CO2 than you would at a welding supply. The trade-off is convenience: paintball shops are often in retail areas, have flexible hours, and understand the regulators and fittings on paintball equipment.
One limitation: paintball shops usually only handle tanks up to about 20 pounds. If you have a larger tank, you'll need a welding supplier instead.
Aquarium stores refill CO2 for planted tanks
Aquarium retailers refill CO2 systems designed for planted tanks. These setups use smaller tanks than paintball or welding applications, and the regulators are different — they're designed to deliver a slow, steady stream of gas into water rather than high pressure for tools. An aquarium store knows these regulators and can refill your tank without damaging the equipment.
Aquarium shops typically charge $10 to $20 per refill and often have tanks in stock if you want to exchange rather than wait. They can also help you troubleshoot if your regulator isn't working or if you're not sure whether your tank is actually empty. Many aquarium stores will refill while you wait, though calling ahead is still a good idea.
If you have a planted tank and bought your CO2 system from an aquarium store, that's your best first call — they know exactly what you have and how to handle it safely.
Sporting goods stores and online retailers offer limited options
Some large sporting goods chains like Dick's Sporting Goods or Academy Sports refill CO2 tanks, but availability varies by location. Call your local store first — not every location has the equipment or staff trained to do refills. When they do offer it, the process is similar to a paintball shop: flat fee, quick turnaround, and limited to smaller tanks.
Online retailers like Amazon sell CO2 cartridges and small tanks, but they cannot refill existing tanks — they only sell new or pre-filled products. Shipping restrictions on pressurized gas mean you cannot mail a tank to a refiller, so online ordering works only if you're buying disposable cartridges or new tanks.
Tank exchanges are faster but cost more over time
Many CO2 retailers offer tank exchanges: you bring in your empty tank, pay a flat fee (usually $20 to $35), and walk out with a full tank when ready. You don't wait for a refill, and you don't need to own the tank. The downside is that you pay more per pound of CO2 than you would with a traditional refill, and you lose track of which tank is yours.
Tank exchanges work well if you use CO2 frequently and value speed over cost. They're common at welding suppliers, paintball shops, and some aquarium stores. Ask whether the shop offers exchanges when you call — some locations do, and some don't.
How to find a refiller near you
Start by searching "CO2 refill near me" or "welding supply [your city]" in Google Maps. Welding suppliers will show up first, and you can call to confirm they refill the size tank you have. If you have a paintball marker, search "paintball shop near me" instead — these shops are usually faster for small tanks.
If you bought your tank from a specific retailer, call them first. They almost always refill tanks they sold, and they know your tank's specifications. If you inherited or borrowed a tank and don't know where it came from, bring it to a welding supplier — they can identify it and refill it regardless of origin.
Before you go, call ahead. Ask whether they refill your tank size, what they charge, whether you need an appointment, and whether they require a deposit if you don't own the tank. This five-minute call saves a wasted trip.
Frequently Asked Questions
Can I refill a CO2 tank myself at home?
No. Refilling a pressurized CO2 tank requires specialized equipment and training to do safely. Attempting it at home risks tank rupture, gas leaks, and injury. Always use a professional refiller.
What if I have a tank but don't know what size it is?
The size is stamped on the tank itself, usually near the top or on the collar. It will say something like "5 lb" or "20 lb". If you can't find it, bring the tank to a welding supplier — they can identify it by weight and markings.
How long does a CO2 refill take?
Small tanks (under 10 pounds) usually refill in 5 to 15 minutes while you wait. Larger tanks may take 30 minutes to an hour, or may require you to leave it and pick it up later. Paintball shops are fastest; welding suppliers vary by location and how busy they are.
Do I need to own the tank to get it refilled?
No, but you may pay a deposit if you don't. Most welding suppliers will refill a borrowed tank if you show ID and a credit card. Paintball shops and aquarium stores usually don't require ownership. Ask when you call.
What's the difference between refilling and exchanging a tank?
Refilling means your tank gets emptied and filled with fresh CO2 — you keep the same tank. Exchanging means you trade your empty tank for a full one and pay a flat fee. Exchanges are faster but cost more per refill over time.