Bridge Cost Estimator
Estimate the cost to bridge from Ethereum mainnet to an L2 using each network's official native bridge. Uses live ETH price and current mainnet gas — defaults pre-fill from the live tracker.
Bridge cost breakdown
What this doesn't include
- Third-party bridge fees. Across, Hop, Stargate, Synapse, and similar paid bridges charge a protocol fee on top of gas — usually 0.05–0.3% of the transferred amount in exchange for faster delivery (seconds-to-minutes vs the ~10-minute / 7-day window on native bridges).
- Token-specific gas. Bridging a custom ERC-20 can use slightly more gas than the estimate above. Stablecoins (USDC, USDT) are close to the median.
- Withdrawal back to mainnet. Going the OTHER direction (L2 → mainnet) on optimistic rollups (Arbitrum, Optimism, Base) requires a 7-day challenge window plus a separate L1 finalization tx — that's much more expensive than the deposit direction. Use a paid bridge for fast L2 → L1 moves.
- The amount you bridge. Gas cost is a function of contract complexity, not value moved. Bridging $50 costs the same in gas as bridging $50,000.
Native bridge deposit cost by L2 — worked example
The deposit gas is fixed per network — it's the same whether you bridge $50 or $50,000. Here's the mainnet cost of an official native-bridge deposit at two gas levels, assuming ETH ≈ $3,000 (the live tool above uses the current gas and ETH price instead):
Illustrative example only — assumes ETH = $3,000 and the fixed Gwei levels shown. Use the live estimator above for current values.
| Destination L2 | Deposit gas | @ 10 Gwei | @ 30 Gwei |
|---|---|---|---|
| Arbitrum | ~92,000 | ~$2.76 | ~$8.28 |
| Polygon PoS | ~95,000 | ~$2.85 | ~$8.55 |
| Optimism | ~130,000 | ~$3.90 | ~$11.70 |
| Base | ~130,000 | ~$3.90 | ~$11.70 |
The spread between cheapest and most expensive native bridge is only ~$3 at normal gas — too small to drive your choice. Pick the L2 on dApps, liquidity, and where you actually want your funds; the bridge cost is a rounding error next to that. For ERC-20s, add a one-time ~46,000-gas approval on your first deposit of each token.
Frequently asked questions
How much does it cost to bridge ETH to Arbitrum?
On the official Arbitrum native bridge, the deposit transaction uses about 92,000 gas on mainnet. At 30 Gwei and ETH = $3,000 that's ~$8.30. The L2-side claim is automatic (no extra tx). Use the calculator above with current gas for the live number.
Why does the bridge cost not depend on the amount I send?
Gas cost is a function of contract execution complexity, not value moved. Bridging $50 or $50,000 of ETH calls the same contract function with the same gas usage. The only thing the amount affects is opportunity cost (transferring more makes the fee a smaller percentage).
What about Across, Hop, or Stargate — are those cheaper?
Often yes for small transfers because they don't require an L1 transaction at all — they use liquidity pools to deliver funds in seconds. The trade-off is a protocol fee (0.05–0.3% of amount) on top of L2-side gas. For amounts under ~$500 a paid bridge usually wins; over $5,000 the native bridge is cheaper. The estimator above only covers native bridges.
Is it cheaper to bridge during off-peak hours?
Yes — significantly. Mainnet gas swings 50–80% between peak (US business hours) and off-peak (late UTC nights, weekends). A bridge tx that costs $15 at 14:00 UTC might cost $4 at 04:00 UTC. Time it if you're not in a rush.
What's the cheapest L2 to bridge to?
For native bridges, Arbitrum and Polygon PoS use slightly less mainnet gas (~92–95k) vs Optimism and Base (~130k). The difference is small in absolute terms — at 30 Gwei and ETH $3,000 it's about $3 between cheapest and most expensive. Pick the L2 based on dApps and liquidity, not bridge cost.
How long does an L2 bridge actually take?
Native bridge deposits (mainnet → L2): typically 10–15 minutes on Arbitrum, Optimism, Base; about 10 minutes on Polygon. Withdrawals back to mainnet on optimistic rollups (Arbitrum, Optimism, Base): 7 days due to the challenge period. Polygon withdrawals via the bridge: ~30 min. Paid bridges (Across, Hop, Stargate) deliver in seconds for both directions.
Does this estimate include token approval cost?
No — the estimator covers the deposit transaction only. If you're bridging an ERC-20 (USDC, USDT, etc.) the first deposit also needs an approval tx (~46k gas one-time). Subsequent bridges of the same token skip the approval.
Already on an L2?
Compare live gas across Arbitrum, Optimism, Base, and Polygon — sorted cheapest first.