Reference

The four fee layers retail traders forget about.

Network gas, broker spread, exchange commission, and bridge cost. Each one is small in isolation; in aggregate they routinely exceed 5 % of a round-trip trade for retail-sized DeFi activity.

1. Network gas

The fee paid to validators/miners for processing the on-chain transaction. Denominated in the blockchain's native token (ETH for Ethereum, BTC for Bitcoin, SOL for Solana).

Order-of-magnitude figures in May 2026:

Chain	Typical simple-transfer fee	Typical DEX swap fee	Cost in USD (varies with price)
Bitcoin	~10 sat/vB	N/A on L1	$1–10
Ethereum L1	~25 gwei	~120 gwei	$5–60
Arbitrum / Optimism (L2)	N/A direct	L1 batch share	$0.20–2
Base (L2)	N/A direct	L1 batch share	$0.10–1
Solana	~5,000 lamports	~50,000 lamports	$0.001–0.05
BNB Chain	~5 gwei	~10 gwei	$0.10–0.50

2. Broker / exchange spread

The bid-ask spread on the trading venue. Centralised exchanges typically charge 0.1–1.5 % spread on retail trades. DEXs (Uniswap, Curve, dYdX) charge a protocol fee of 0.05–0.30 % plus the bid-ask spread of the underlying liquidity pool, which can spike under low liquidity.

Spread is the easiest cost to overlook because it's not itemised — you just receive a slightly different price than the displayed mid-market quote. The calculator's “broker fee %” field handles this; enter 0.5–1.0 % as a reasonable default for centralised retail exchanges.

3. Exchange commission

An explicit per-trade fee, separate from the spread. Distinguish between maker fees (lower, for limit orders that add liquidity) and taker fees (higher, for market orders that consume liquidity). Common retail figures:

Coinbase Advanced: 0.40 % taker, 0.25 % maker (high tier).
Kraken: 0.26 % taker, 0.16 % maker (high tier).
Binance: 0.10 % taker, 0.10 % maker (with BNB discount, can drop to 0.075 %).
Coinbase “Simple Buy/Sell”: 1.49 % + spread, marketed as a single “flat fee”.

4. Bridge cost

If you move tokens between chains (Ethereum → Arbitrum, Solana → Ethereum), you pay a bridge fee. The fee can be modest (0.1–0.3 % on canonical bridges like Hop or Across) or substantial (3–5 % on lesser-used or wrapped-asset bridges).

The bridge trap. A trader notices ETH is cheaper on Arbitrum than on Ethereum L1, bridges $10,000, swaps to USDC, bridges back. The notional “arbitrage” is wiped out by bridge fees plus gas plus swap spread — net result is typically a small loss. Cross-chain arbitrage at retail size is rarely profitable; specialised MEV bots capture the genuine opportunities within milliseconds.

The cumulative effect

For a retail trader making twelve round-trip swaps per year on Ethereum L1 with average DEX fees, total fee load can easily reach 8–12 % of the position size annualised. On Layer 2s (Arbitrum, Optimism, Base) the equivalent figure drops to 1–3 %. On centralised exchanges with spread + commission only, it's typically 1–2.5 %.

The implication is that the ROI hurdle for active trading on Ethereum L1 is materially higher than on cheaper venues. A strategy that works on Solana at 30bp round-trip cost may not be profitable on Ethereum L1 at 100bp+ cost.