AMM Slippage Calculator
Automated market makers (AMMs) like Uniswap use a constant-product formula (x * y = k) to determine swap prices. As you buy one token, its price rises because the pool becomes more scarce of it. For small trades relative to pool size, slippage is minimal. For large trades, price impact can be substantial. This calculator takes the current pool reserves of both tokens and the amount you want to swap in, then computes how many tokens you receive out, the effective exchange rate, and the slippage percentage compared to the pool's spot price before the trade. This is essential for large DeFi trades where optimizing execution price matters.
AMM constant-product formula
k = Reserve X * Reserve Y
New Reserve X = Reserve X + Swap In
Tokens Out = Reserve Y - (k / New Reserve X)
Spot Price = Reserve Y / Reserve X
Effective Price = Tokens Out / Swap In
Slippage = (Spot Price - Effective Price) / Spot Price * 100
Note: real DEXs apply a swap fee (e.g., 0.30% for Uniswap v2) that reduces the amount received. This calculator shows the no-fee case; multiply Tokens Out by (1 - fee rate) for the actual amount received.
Price impact thresholds
- Under 0.1%: excellent execution, trade is small relative to pool depth.
- 0.1-0.5%: acceptable for most trades on major pools.
- 0.5-1.0%: moderate impact; consider splitting the trade or using an aggregator.
- Above 1.0%: high impact; a significant portion of value is lost to the pool LPs. Strongly consider alternative routing.
- Above 5.0%: very high impact; only acceptable for illiquid pairs with no better alternative.
AMM slippage: frequently asked questions
What is AMM slippage?
Slippage is the difference between the expected price and the actual execution price of a trade on a decentralized exchange. In a constant-product AMM, larger trades move the price more, causing greater slippage. Slippage = (Effective price - Spot price) / Spot price * 100.
What is the constant-product formula?
The constant-product formula is x * y = k, where x and y are the reserves of the two tokens and k is a constant. When you swap dx of token X, the new reserve of X is x + dx, and the new reserve of Y must satisfy (x + dx) * y_new = k, so y_new = k / (x + dx). You receive y - y_new of token Y.
What is price impact vs slippage?
Price impact is the change in the pool's marginal price caused by your trade. Slippage is the difference between the quoted price at the time you submit the transaction and the actual price at execution. Slippage includes price impact plus any price movement between submission and confirmation.
How can I reduce slippage?
Trade smaller amounts relative to pool size, choose pools with higher liquidity (larger reserves), split large trades into multiple smaller ones, or use aggregators that route through multiple pools to minimize price impact.
What is a slippage tolerance setting?
Slippage tolerance is the maximum acceptable slippage you set before submitting a trade. If the actual slippage exceeds your tolerance, the transaction reverts. A 0.5% tolerance is common for stablecoin pairs; 1-2% for volatile pairs on active pools.
Official sources
- Uniswap Foundation: Uniswap v2 Core Whitepaper (Adams et al.).
- Ethereum Foundation: Decentralized Finance (DeFi).
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.