Uniswap Gas Fee on Optimism
How much does a Uniswap swap cost on Optimism right now? The card below shows today's live USD fee for a typical V3 swap on Optimism, split into its two parts. Optimism is the original optimistic rollup — the chain whose OP Stack now also powers Base.
Live Uniswap swap cost on Optimism
~150,000 gas · 0.0010 Gwei · ETH ≈ $1,669.24
Total fee
$0.000282
= $0.000250 L2 execution
+ $0.00003115 L1 data fee
Includes the L1 data/security fee (queried live from the GasPriceOracle predeploy). L1 fee dominates the tiny L2 execution cost on OP Stack chains. The L1 data portion is estimated from current L1 pricing and a representative payload — your exact fee varies with the token and route.
Optimism and Base price swaps the same way
Optimism built the OP Stack; Base runs on it. So if you've compared the two and found the numbers eerily close, that's why — they use the same fee formula:
- L2 execution. The swap runs on Optimism's execution layer for a tiny fraction of a cent.
- L1 data fee. Optimism posts your compressed transaction to Ethereum for security and charges your share of that cost — the dominant part of the bill, priced live from current L1 data/blob pricing via the OP Stack gas-price oracle.
Because the mechanics are identical, picking between Optimism and Base for a single swap is really a live-price coin-flip — sometimes one is a hair cheaper than the other. Where they differ more is liquidity and which apps are deployed.
Optimism vs mainnet — the identical swap
The same ~150,000-gas Uniswap swap on Ethereum mainnet, live:
Live Uniswap swap (mainnet) cost
150,000 gas units · ETH ≈ $1,669
Standard
$0.0964
0.385 Gwei
Lowest tier that confirms in a few minutes.
Fast
$0.1566
0.625 Gwei
Default wallet tier — confirms in about a minute.
Rapid
$0.4037
1.61 Gwei
Top priority — confirms in under 30 seconds.
Base fee right now: 0.356 Gwei. Tier prices add the average priority tip seen in recent blocks. Wallets often pad estimates by 10–30%, so your actual quote may be a bit higher.
Most weeks Optimism runs an order of magnitude or more below the mainnet card. The gap is widest precisely when mainnet is congested — the moment a cheap swap matters most.
Getting onto Optimism to swap
As with any L2, you need ETH on Optimism for gas — bridged from mainnet, and the bridge transaction itself pays mainnet gas. One small swap may not justify the bridge; several swaps, or funds you already hold on Optimism, tip the math firmly in the L2's favor.
See the live cheapest bridge to Optimism to minimize that one-time cost.
Optimism vs the other L2s for a swap
- • Optimism and Base — near-identical OP Stack pricing; total swings with mainnet's L1 fee.
- • Arbitrum — one bundled figure, deepest L2 liquidity, steadier total.
- • Polygon — frequently a fraction of a cent, but a sidechain with a different security model.
The cheapest L2 shifts week to week — the live L2 comparison shows the current ranking before you bridge.
Frequently asked questions
How much does a Uniswap swap cost on Optimism right now?
The live figure in the card above is the current cost of a typical Uniswap V3 swap on Optimism, updated every minute. It is usually a few cents — like Base, Optimism is an OP Stack chain, so the total tracks Ethereum mainnet through its L1 data fee.
Is Optimism cheaper than Base for a swap?
They are usually within a hair of each other. Base is built on the OP Stack that Optimism created, so the two share almost identical fee mechanics — L2 execution plus an L1 data fee. Which is cheaper on a given day comes down to small differences in their L1-fee scalars and current load. Check the live comparison.
Why does an Optimism swap cost more when Ethereum is congested?
Optimism posts your transaction data to Ethereum L1 for security, and that L1 data fee is priced in mainnet terms. When mainnet gas rises, the L1 portion of every Optimism transaction rises too — though far less than paying full mainnet gas.
What is the Superchain and does it change gas?
The Superchain is the network of OP Stack chains (Optimism, Base, and others) that share the same technology and a common bridging standard. It does not change how an individual swap is priced — each chain still charges L2 execution plus its own L1 data fee — but it means moving between these chains is increasingly standardized.
Is the Uniswap interface the same on Optimism?
Yes — the same Uniswap protocol and app.uniswap.org, you just switch your wallet to Optimism. Gas is paid in ETH, so you need a small ETH balance on Optimism, bridged from mainnet.
Do I pay a token approval fee on Optimism?
The first swap of a given ERC-20 needs an approve(), but it costs cents on Optimism. The Uniswap UI routes through Permit2, which folds the approval into the swap so first-time swaps cost about the same as repeat ones.
Optimism or Base — which is cheaper right now?
They're usually neck and neck. See live swap costs across all four major L2s in one table and pick the cheapest this minute.