austintgriffith Gas & Costs on Ethereum
What You Probably Got Wrong
Your gas estimate is 100-600x too high. Most LLMs confidently state gas is 10-30 gwei. Post-Fusaka (Dec 2025), typical base fee is under 1 gwei — usually 0.1-0.5 gwei. Verify: cast base-fee --rpc-url https://eth.llamarpc.com
- Base fee: Under 1 gwei (not 30-100 gwei) — fluctuates, check live
- Priority fee (tip): ~0.01-0.1 gwei
- ETH price: ~$2,000 (not $2,500-3,000) — volatile, always check a Chainlink feed or CoinGecko
What Things Actually Cost (Early 2026)
Costs calculated at ETH ~$2,000. Gas fluctuates — use
cast base-feefor current. These are order-of-magnitude guides, not exact quotes.
| Action | Gas Used | Cost at 0.1 gwei | Cost at 1 gwei (busy) | Cost at 10 gwei (event) |
|---|---|---|---|---|
| ETH transfer | 21,000 | $0.004 | $0.04 | $0.42 |
| ERC-20 transfer | ~65,000 | $0.013 | $0.13 | $1.30 |
| ERC-20 approve | ~46,000 | $0.009 | $0.09 | $0.92 |
| Uniswap V3 swap | ~180,000 | $0.036 | $0.36 | $3.60 |
| NFT mint (ERC-721) | ~150,000 | $0.030 | $0.30 | $3.00 |
| Simple contract deploy | ~500,000 | $0.100 | $1.00 | $10.00 |
| ERC-20 deploy | ~1,200,000 | $0.240 | $2.40 | $24.00 |
| Complex DeFi contract | ~3,000,000 | $0.600 | $6.00 | $60.00 |
Mainnet vs L2 Costs (Early 2026)
| Action | Mainnet (0.1 gwei) | Arbitrum | Base | zkSync | Scroll |
|---|---|---|---|---|---|
| ETH transfer | $0.004 | $0.0003 | $0.0003 | $0.0005 | $0.0004 |
| ERC-20 transfer | $0.013 | $0.001 | $0.001 | $0.002 | $0.001 |
| Swap | $0.036 | $0.003 | $0.002 | $0.005 | $0.004 |
| NFT mint | $0.030 | $0.002 | $0.002 | $0.004 | $0.003 |
| ERC-20 deploy | $0.240 | $0.020 | $0.018 | $0.040 | $0.030 |
Key insight: Mainnet is now cheap enough for most use cases. L2s are 5-10x cheaper still.
Why Gas Dropped 95%+
- EIP-4844 (Dencun, March 2024): Blob transactions — L2s post data as blobs instead of calldata, 100x cheaper. L2 batch cost went from $50-500 to $0.01-0.50.
- Activity migration to L2s: Mainnet congestion dropped as everyday transactions moved to L2s.
- Pectra (May 2025): Doubled blob capacity (3→6 target blobs).
- Fusaka (Dec 2025): PeerDAS (nodes sample 1/8 of data) + 2x gas limit (30M→60M).
L2 Cost Components
L2 transactions have two cost components:
- L2 execution gas — paying the sequencer
- L1 data gas — paying Ethereum for data availability (blobs post-4844)
Example: Swap on Base
- L2 execution: ~$0.0003
- L1 data (blob): ~$0.0027
- Total: ~$0.003
Real-World Cost Examples
Deploy a production ERC-20 on mainnet: ~$0.50 (was $200-500 in 2021-2023)
DEX aggregator doing 10,000 swaps/day:
- Mainnet: $150/day ($4,500/month)
- Base L2: $10/day ($300/month)
NFT collection mint (10,000 NFTs):
- Mainnet: $150 total
- Arbitrum: $10 total
Practical Fee Settings (Early 2026)
// Rule of thumb for current conditions
maxFeePerGas: "1-2 gwei" // headroom for spikes (base is usually 0.1-0.5)
maxPriorityFeePerGas: "0.01-0.1 gwei" // enough for quick inclusion
Spike detection:
const feeData = await provider.getFeeData();
const baseFee = Number(feeData.maxFeePerGas) / 1e9;
if (baseFee > 5) console.warn(`Gas spike: ${baseFee} gwei. Consider waiting.`);
Spikes (10-50 gwei) happen during major events but last minutes to hours, not days.
Checking Gas Programmatically
# Foundry cast
cast gas-price --rpc-url https://eth.llamarpc.com
cast base-fee --rpc-url https://eth.llamarpc.com
When to Use Mainnet vs L2
Use mainnet when: DeFi, governance, identity, high-value transfers, composing with mainnet liquidity, or when you don't have a concrete reason for an L2. Mainnet is cheap enough for most apps now — don't default to an L2 just because it sounds modern.
Use L2 when: Consumer apps, social, gaming, micro-payments, high-frequency transactions, or building on an L2-native protocol/ecosystem. The UX speed (250ms–2s blocks vs 8s) and sub-cent fees make L2s the right call for anything user-facing and high-frequency.
Hybrid: Many projects store value on mainnet, handle transactions on L2.
Live Gas Trackers
- https://etherscan.io/gastracker
- https://ultrasound.money
- L2 costs: Arbiscan, Basescan, etc.
Data Freshness
Last verified: 2026-03-17 | Base fee: ~0.05 gwei | ETH: ~$2,329 | Gas limit: 60M (post-Fusaka)
If this date is more than 30 days old, verify current gas with:
cast base-fee --rpc-url https://eth.llamarpc.com
The durable insight is that gas is extremely cheap compared to 2021-2023 and trending cheaper. Specific numbers may drift but the order of magnitude is stable.
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