Uniswap Gas Fee Right Now

Why a Uniswap swap costs what it costs

A swap is the most expensive routine action on Ethereum because the contract does roughly seven things in one transaction:

1. Verify the caller's signature and check the pool exists
2. Read the current pool state (token balances, current tick on V3)
3. Compute the swap math — for V3, this means walking through liquidity ticks until the input is consumed
4. Update the pool state (balances, tick position, fee accumulators)
5. Transfer the input token from the user into the pool
6. Transfer the output token from the pool to the user
7. Emit the Swap event for off-chain indexers

Each step costs gas. The total varies by Uniswap version, pool depth, and how many ticks the swap crosses:

Uniswap V4 shipped in 2025 with a hook-based architecture: pools can run custom code before and after every swap. Hooks let pool creators add functionality (limit orders, dynamic fees, MEV protection) but also let them inject computational cost. A V4 swap through a vanilla pool is cheaper than V3; through a hook-heavy pool, it can be more expensive. Always check the pool you're routing through.

Approval gas — the hidden first-time cost

The first time you swap a given ERC-20 token on Uniswap, you pay an extra ~45,000 gas for an approve() call — granting the Uniswap router permission to move that token from your wallet. That's a separate transaction with its own fee. On mainnet at peak gas, the approval alone can cost $5-15 before you even swap.

Two ways to reduce this:

• Approve unlimited. When the wallet prompts you to approve, set the cap to “unlimited” (max uint256) instead of just the swap amount. Future swaps of the same token skip the approval entirely. Cost saving: one approval covers an infinite number of swaps. Security tradeoff: if Uniswap's router contract is ever compromised, the attacker could drain your full balance of that token — limited but not zero risk.
• Use Permit2. The Uniswap interface now routes through Permit2 — a separate contract that consolidates approvals across all Uniswap-integrated apps with one signature. Permit2 approvals are off-chain signatures (no gas) the first time, and the on-chain transfer happens as part of the swap itself rather than a separate transaction. Net: a first-time swap with Permit2 costs roughly the same as a repeat swap. This is the default on the Uniswap UI as of 2024-2025.

When swaps cost more than expected

Three specific patterns where your actual swap bill comes in higher than the table above suggests:

• Large swaps in shallow pools. A $50,000 swap in a pool with $200,000 of liquidity will cross many V3 ticks, pushing gas to 250,000-400,000. The Uniswap router will warn about price impact, but the gas cost rises with it. For large trades, split into multiple smaller swaps or use a DEX aggregator that splits routing across pools.
• Long-tail tokens with custom transfer logic. Some tokens (rebasing tokens, fee-on-transfer tokens, deflationary tokens) implement non-standard transfer() logic. The Uniswap router has special handling for these (the swapExactTokensForTokensSupportingFeeOnTransferTokens function name says it all) and that costs more gas — typically 30-50% more than a vanilla swap.
• DEX aggregator routing. When you swap through 1inch, Matcha, or another aggregator, the swap may route through Uniswap PLUS Curve, Balancer, or Sushi. You get a better output price, but each venue adds gas. Gas-vs-output tradeoff varies; for $1,000+ swaps the better price almost always wins. For $100 swaps, going direct to Uniswap is often cheaper all-in.

When is the cheapest time to swap on Uniswap?

Uniswap gas tracks mainnet base fee, so the cheapest swap windows are the cheapest mainnet windows. On a typical week the gap between peak and off-peak Uniswap gas can be 5–10x.

• • Late night UTC (02:00–06:00) on weekdays
• • Most of Saturday and Sunday
• • Right after a major mint or token launch resolves

Browse the cheap gas times heatmap for this week's pattern.

How to swap on Uniswap for less

• Use Uniswap on an L2. Uniswap is deployed on Arbitrum, Optimism, Base, and Polygon. Same UI, swaps usually under $1.
• Pick Standard tier. The wallet defaults to Fast. For a routine swap, Standard is fine.
• Pre-approve tokens once. First-time swaps require an approval (~45,000 gas extra). Approve a generous cap once so future swaps skip that step.
• Avoid swap-during-mint days. Major mainnet congestion can quadruple Uniswap gas. Wait a few hours.
• Batch via DEX aggregators. Aggregators sometimes route through gas-cheaper venues even when the headline price is the same.

Frequently asked questions