Free CEX-DEX Real-Time Arbitrage Calculator: Calculate Your Edge in Seconds

How CEX-DEX Real-Time Arbitrage Works (Formula Explained)

CEX-DEX arbitrage exploits temporary price divergences between centralized exchanges (CEX) such as Binance, Coinbase, or Kraken and decentralized exchanges (DEX) such as Uniswap V3, Curve, or PancakeSwap. The strategy works because CEX order books and DEX automated market makers (AMMs) update on different latency cycles, creating windows of several seconds where the same asset trades at different prices on each venue.

Note that Bitcoin does not exist natively on Ethereum or Layer 2 networks: on a DEX you trade Wrapped Bitcoin (WBTC), an ERC-20 token backed 1:1 by BTC custodied by BitGo. Liquidity for WBTC concentrates in Uniswap V3 pools paired with WETH or USDC. Other wrapped variants exist (cbBTC, tBTC), but WBTC remains the deepest market as of 2026.

This calculator implements the standard six-variable model used by professional arbitrage desks:

• Spread (%) = ((P_dex − P_cex) / P_cex) × 100
• Notional (USD) = P_cex × Trade Size
• Gross Profit (USD) = (P_dex − P_cex) × Trade Size
• Total Fees (USD) = (Notional × CEX_fee) + (Notional × DEX_fee) + Gas Fee
• Net Profit (USD) = Gross Profit − Total Fees
• ROI (%) = (Net Profit / Notional) × 100
• Breakeven Spread (%) = (Total Fees / Notional) × 100

The Breakeven Spread is the most underused output. It represents the minimum price gap at which the trade stops losing money — below that threshold, every fill is unprofitable regardless of execution speed. Most retail traders fixate on the headline spread; professionals fixate on the gap between spread and breakeven, because that gap is the actual safety margin against slippage and latency.

Worked Example: 1 BTC Arbitrage Between a CEX and Uniswap V3 (Illustrative)

The following is an illustrative scenario using round numbers in the same range BTC has traded in 2026. Real spot prices fluctuate continuously — the calculator above accepts your live inputs, while this example walks through the mechanics. Assume:

• CEX Price (Binance spot): $80,000
• DEX Price (Uniswap V3 WBTC pool): $80,560
• Trade Size: 1 BTC
• CEX Taker Fee: 0.10%
• DEX Swap Fee: 0.30%
• Gas Fee: $2.50 (Ethereum mainnet, normal hours)

Step 1 — Spread: ((80,560 − 80,000) / 80,000) × 100 = 0.700%

Step 2 — Notional: 80,000 × 1 = $80,000

Step 3 — Gross Profit: (80,560 − 80,000) × 1 = $560.00

Step 4 — Total Fees: CEX fee 80,000 × 0.001 = $80.00; DEX fee 80,000 × 0.003 = $240.00; Gas $2.50. Total: $322.50

Step 5 — Net Profit: 560.00 − 322.50 = +$237.50

Step 6 — ROI: (237.50 / 80,000) × 100 = 0.297%

Step 7 — Breakeven Spread: (322.50 / 80,000) × 100 = 0.403%

How to read this result: the headline spread is 0.700%, but only 0.297% becomes ROI on capital deployed. The remaining 0.403% is consumed entirely by fees — and the trade only stops being a loss above that 0.403% breakeven threshold. If the spread shrinks below 0.403% during execution (which happens routinely due to slippage and latency, as discussed below), the trade flips to a net loss even though the displayed spread initially looked profitable.

What Most CEX-DEX Arbitrage Calculators Miss

The basic six-variable model assumes a frictionless world where prices stay still during execution. In practice, they don't. Four costs are systematically ignored by generic calculators — and they turn a large fraction of "profitable on paper" arbitrages into losses on settlement:

1. Slippage on the DEX side. A 1 BTC swap on Uniswap V3 against the WETH-WBTC 0.3% pool typically incurs an additional 0.05–0.15% in price impact depending on pool depth at trade time. For a 0.700% headline spread, that single factor consumes 7–22% of your gross profit before any other cost.

2. Failed transactions. When you submit a DEX trade, you pay gas regardless of whether the swap succeeds. If a competing arbitrageur fills first or the pool moves past your slippage tolerance, the transaction reverts and the gas is lost. Failure rates of 15–25% are common for competitive arbs on Ethereum mainnet during volatile hours, which means your effective gas cost is roughly 1.2–1.3x what a single-trade calculation suggests.

3. Latency between the CEX leg and the DEX leg. The CEX side fills in under 100ms via REST or WebSocket. The DEX side waits for the next block: approximately 12 seconds on Ethereum mainnet, 250ms–2s on Arbitrum One, Optimism, and Base. During that window, the price can — and frequently does — move against you, sometimes erasing the entire spread before the second leg lands.

4. MEV (Maximum Extractable Value) competition. Specialized bots monitor the public mempool and front-run profitable arbitrage opportunities by paying higher gas tips to validators. Public datasets from Flashbots and EigenPhi consistently show that a majority of profitable CEX-DEX opportunities are captured by MEV searchers within the same block in which they appear.

This calculator gives you a clean theoretical baseline, useful for sizing trades and screening opportunities. Real execution typically delivers 30–60% less than the theoretical net profit on a normal day, and substantially less during volatile market conditions.

Real-World Considerations: Latency, Gas Spikes, L2 Sequencers, and Funding

If you trade this strategy with real capital, four risks need explicit mitigation beyond the calculator output:

Block time and execution windows. On Ethereum mainnet, blocks finalize every ~12 seconds. On Arbitrum One, Optimism, and Base — the three dominant L2s as of 2026 — block times range from 250ms to 2 seconds, but each rollup currently relies on a single sequencer operated by the rollup team. Sequencer downtime is rare but non-zero: Arbitrum experienced a 78-minute outage in December 2023 and a 50-minute one in June 2024. During downtime, your DEX leg cannot execute while your CEX leg may have already filled, leaving you with one-sided directional exposure.

Gas spikes during volatility. Ethereum mainnet base fee typically sits in the 20–50 gwei range during normal hours, but spikes to 200–500 gwei during NFT mints, token launches, or sharp market moves. A trade that's profitable at $2.50 in gas can become a $25 loss at $25 gas. Always model the worst-case gas scenario, not the rolling average.

Funding rate exposure on hedged variants. If you hedge the CEX leg with a perpetual futures short instead of holding spot, you pay funding to longs when funding is positive and receive it when negative. On bullish days, perp funding rates of 0.01–0.03% per 8-hour window are typical on major venues, which compounds to 0.03–0.09% per day eroding your accumulated arbitrage spread.

Withdrawal and bridge fees on cross-chain variants. If your CEX and DEX live on different chains, bridge costs are additive. Native rollup bridges to L2s currently charge 0.05–0.10%; third-party bridges such as Stargate, Across, and Synapse charge 0.10–0.30% plus gas. These fees are not included in the calculator above and need to be added manually for any cross-chain scenario.

Common Mistakes in Arbitrage Profit Calculations

Five errors appear consistently in retail-level arbitrage spreadsheets and calculators:

Calculating ROI on the spread instead of the capital. A 0.700% spread is not a 0.700% return. ROI is measured against the capital deployed (the notional), not the price gap. The correct formula is Net Profit divided by Notional, which is what this calculator uses. Reporting spread as ROI overstates returns by a factor of 2x or more in most realistic scenarios.

Forgetting that fees apply to the full notional, not the spread. A 0.10% CEX fee on an $80,000 notional is $80, not 0.10% of the $560 gross profit. This single misapplication is the most common error in beginner spreadsheets and produces results that are off by an order of magnitude.

Assuming simultaneous execution. No CEX-DEX arbitrage executes both legs at the same instant. There is always a delay of at least a few hundred milliseconds and often several seconds. Treating the trade as atomic in your model understates risk by exactly the amount of price movement during that delay window.

Ignoring the breakeven threshold. Many retail traders enter trades where the spread is positive but below the breakeven line. The trade looks profitable on paper and loses money on settlement. Always check the breakeven output of the calculator before committing capital — as a rough rule, if the displayed spread is less than 1.5x the breakeven, the safety margin is too thin to absorb normal slippage and latency.

Not modeling failed transactions. If 1 in 5 trades reverts on the DEX side, your effective gas cost is 1.25x what the calculator shows (you pay gas five times to land four trades). Multiply your gas input by 1.25 to get a more realistic cost basis on Ethereum mainnet during competitive hours, or by 1.10 on L2s where contention is lower.

For a deeper treatment of the full methodology behind these calculations, including data sources and review cadence, see our methodology page. All numerical outputs are theoretical estimates as defined in the disclaimer.