You can do the exact same swap on two different platforms, both advertising a "0.3% fee," and walk away with noticeably different amounts of tokens. The fee is the sticker price. The execution price is what you actually pay. This guide breaks down what really drives the cost of a crypto swap, and how to consistently get the cheapest one.
The three things that decide what a swap really costs you
1. Network fees (gas). Every on-chain swap pays the blockchain to process it. On Ethereum mainnet this can be the biggest cost of all, especially for smaller trades. On Layer 2s like Base and Arbitrum, and on Solana, it's often a few cents. Same swap, wildly different gas — just by choosing where you do it.
2. Slippage and price impact. When you trade against a liquidity pool, your own trade moves the price. Trade against a thin pool and you "impact" the price a lot — you get fewer tokens than the quote suggested. Bigger, deeper routes barely move. This is the cost people never see because it's baked into the amount they receive.
3. Routing. This is the quiet one. Your trade has to travel through liquidity somewhere. A single exchange only has its own pools to offer you. If a better price exists two clicks away on another exchange, a single DEX won't find it — and you'll never know you left money on the table.
Put simply: the cheapest swap isn't the one with the lowest advertised fee. It's the one where gas, slippage, and routing all line up in your favor.
Why a DEX aggregator is usually the cheapest route
A DEX aggregator exists to solve the routing problem. Instead of checking one exchange, it scans many at once, and can even split a single trade across several pools to squeeze out a better overall price. You get the best on-chain price available in that moment, without manually comparing five apps yourself.
That's the entire idea behind Kryllex: it routes your swap across multiple decentralized exchanges on Ethereum, Base, Arbitrum, Solana and more, then executes the cheapest path — while you keep custody of your funds the whole time.
Chain by chain: where swaps are cheapest
- Ethereum mainnet: deepest liquidity, but gas is the tax. Best for larger swaps where a great price outweighs a higher network fee.
- Base: low fees and fast-growing liquidity — often the sweet spot for everyday swaps. See our step-by-step Base guide.
- Arbitrum: low fees, mature liquidity, strong for a wide range of pairs.
- Solana: very low fees and fast finality — great for smaller, frequent swaps. Here's how to swap on Solana.
A practical rule of thumb: if your trade isn't huge and the token exists on an L2 or Solana, doing it there instead of Ethereum mainnet usually saves the most.
The 30-second habit that keeps every swap cheap
Before you sign any transaction, compare the output amount — not the fee. Same tokens, same moment, look at how many tokens you'd actually receive on a couple of routes. An aggregator does this comparison for you, but the habit matters: the number to protect is what lands in your wallet, not the percentage on the label.
Two more quick wins:
- Mind your slippage tolerance. Too tight and your swap fails; too loose and you invite a worse fill. Most wallets and aggregators set a sensible default — only widen it for illiquid tokens, and know that's a trade-off.
- Batch when you can. Fewer, larger swaps generally beat many tiny ones, because each transaction pays gas.
Cheap and self-custody — you don't have to choose
There's a myth that the cheapest swaps mean handing your coins to a centralized exchange. You don't. A non-custodial aggregator executes the swap straight from your own wallet — you sign, the trade routes to the best price, and you keep your keys throughout. Best price and self-custody aren't a trade-off; they're the default when the tool is built right.
FAQ
Is swapping on a DEX aggregator safe?
A non-custodial aggregator never holds your funds — you sign a transaction from your own wallet. As with any on-chain tool, use audited protocols, double-check you're on the real site (bookmark it to dodge phishing clones), and review the transaction before signing.
Do I need an account to swap?
No. You connect a self-custody wallet and swap. There's no sign-up and no handing over custody.
What's actually the cheapest chain to swap on?
For most everyday trades, a Layer 2 like Base or Arbitrum, or Solana, will be far cheaper on gas than Ethereum mainnet. For very large swaps, Ethereum's deep liquidity can still win on overall price.
Does an aggregator charge more than a single DEX?
Not inherently — and it often saves you more than any small routing fee by finding a better execution price across multiple pools.
Ready to see your best route?
Kryllex compares prices across 16 chains and 100+ DEXs and routes every trade through the cheapest path — non-custodial, no account.
Launch Kryllex →This article is educational and not financial advice. Always do your own research and review transactions before signing.
Keep reading: What is a DEX aggregator? · Non-custodial trading explained