What Are Gas Fees? A Guide for Stablecoin Users
Gas fees are unavoidable — but overpaying isn't. Here's what they are and how to keep them low.
What Are Gas Fees, and Why Do They Exist?
You're about to send some USDC. Before you confirm, your wallet shows a small additional charge you didn't add. No explanation, no breakdown. Just an extra line you weren't expecting. That charge is a gas fee. Once you understand what it is, it stops feeling like a mystery.
Every blockchain transaction needs to be verified and recorded. That work is done by validators: computers on the network that confirm your transfer is legitimate and write it permanently to a shared ledger. Gas fees are what you pay them for that work. Without them, there's no incentive for the network to process anything.
The term "gas" originally comes from Ethereum, where it described the computational effort needed to run a transaction. It's since become the catch-all term for blockchain transaction fees across the industry.
Where Gas Fees Come From
Gas fees are not fixed. They shift depending on two things: which network you're using, and how busy that network is at the time of your transfer.
Different blockchain networks are built with different infrastructure and fee structures. Ethereum, one of the oldest and most widely used networks, tends to carry higher fees — typically ranging from a few cents to several dollars, and occasionally more during periods of heavy demand. Networks like Polygon, Solana, and Tron were built with lower fees in mind. On these networks, the same transfer often costs a fraction of a cent.
The second variable is congestion. When a lot of users are sending transactions at the same time, demand for processing capacity goes up. On some networks, users can pay a higher fee to get their transaction prioritized. During peak periods, this can push costs up considerably.
For most everyday stablecoin transfers, the network you choose has the biggest impact on what you pay. If you want a deeper look at how different networks compare on speed, fees, and reliability, our Blockchain Networks for Beginners article covers this in full.
Why Gas Fees Matter for Everyday Stablecoin Spending
If you're making a single large transfer, a small gas fee is easy to absorb. But if you're funding a card regularly, paying people frequently, or moving stablecoins across wallets often, those fees start to add up. On the wrong network, they can meaningfully eat into the value of smaller transfers.
It's also worth being clear about something: gas fees are set by the network, not by any card provider or platform. When you fund your DeCard, the fee you pay is determined entirely by the blockchain network you've chosen to send on. It goes to the validators processing your transaction, not to DeCard.
This is different from FX fees or conversion costs, which are platform-level charges. Gas fees are a network-level cost, and no platform can waive or absorb them on your behalf. If you're trying to understand the full cost picture of using a stablecoin card, our article on Stablecoin Card Rewards: What You're Actually Keeping After Fees breaks down how these different costs interact.
How to Keep Gas Fees Low
The most effective way to reduce gas fees is to choose a low-fee network when sending stablecoins. Not all networks that support USDT or USDC are equal on cost.
As a general reference: Polygon typically charges under $0.01 per transaction. Solana and Tron are similarly low-cost. Ethereum fees are higher and can climb further when the network is busy. If you have the option to send via Polygon or Solana and the receiving platform supports it, that's usually the more cost-efficient choice.
When funding your DeCard, the supported networks for USDT are Polygon, Solana, Tron, and Ethereum. For USDC, you can send via Polygon, Solana, Base, and Ethereum. For most users, Polygon offers the best balance of low fees and fast confirmation times, typically settling in around two seconds with fees well under a cent.
One thing to watch: always make sure the network you send on matches the network selected in the receiving platform. A mismatch won't result in an extra fee. It may mean your funds don't arrive at all.
For a full step-by-step walkthrough of funding your DeCard, including how to pick the right network and avoid common mistakes, see our guide: How to Fund Your DeCard with Stablecoins in Minutes.
