About the Slippage Calculator
This slippage calculator estimates what you will actually receive when you swap on a constant-product automated market maker (AMM) such as Uniswap v2-style pools. Enter the two pool reserves, the amount you are selling, the pool fee and your slippage tolerance, and it returns the tokens out, the execution price, the price impact and the minimum you will accept.
Price impact is the difference between the pool's current price and the average price you get, caused by your trade moving the reserves. It grows quickly as a trade becomes a larger share of the pool. Slippage tolerance is a separate safety setting: if the price moves against you by more than that percentage before your transaction confirms, the swap reverts.
The model is exact for x·y = k pools with no other trades in the same block. Concentrated-liquidity pools (Uniswap v3/v4) and aggregators that split routes can give better prices, so treat the figure as a conservative estimate for comparable liquidity.
With the default inputs, the tokens received is 29,614.741032. Change any value above to recalculate instantly.
How to use the slippage calculator
- 1Look up the pool's reserves for both tokens on the DEX or a block explorer.
- 2Enter the reserve of the token you sell and of the token you buy.
- 3Enter the amount you want to swap and the pool fee tier.
- 4Set your slippage tolerance.
- 5Check tokens received and price impact; reduce size if impact is high.
Formula and method
A constant-product pool keeps x × y = k. The fee is taken from the input first, then the rest of your tokens are added to the input reserve and enough output tokens are removed to keep the product constant. That gives the amount out, Δy.
Spot price is y ÷ x before the trade. Price impact compares your average price (excluding the fee) with spot and simplifies to Δx(1 − f) ÷ (x + Δx(1 − f)). Total cost versus spot also includes the fee. The minimum received is the quote reduced by your slippage tolerance — the swap reverts if the pool would pay less.
- x
- Pool reserve of the token you sell
- y
- Pool reserve of the token you buy
- Δx
- Amount you sell
- f
- Pool fee as a decimal (0.3% = 0.003)
Worked examples
Sell 10 ETH into a 1,000 ETH / 3M USDC pool
After the 0.3% fee, 9.97 ETH enters the pool, which pays out 3,000,000 × 9.97 ÷ 1,009.97 ≈ 29,614.74 USDC. That averages $2,961.47 per ETH versus a $3,000 spot price — about 0.99% price impact plus the fee. With 0.5% tolerance the swap still succeeds down to 29,466.67 USDC.
Large stablecoin swap in a 500k/500k pool
Swapping 50,000 into a pool holding 500,000 of each stablecoin is 10% of the reserve. Even with a tiny 0.05% fee the constant-product curve pays only 45,433.88 — a 9.1% price impact. Concentrated-liquidity stable pools are designed to avoid exactly this.
Buying a small-cap token with 1% fee
Putting 100,000 of the quote token into a pool with 2,000,000 of it and 1,000 tokens buys about 47.17 tokens instead of the 50 the spot price implies — 4.7% price impact plus the 1% fee, 5.67% in total.
Frequently asked questions
What is the difference between slippage and price impact?+
Price impact is the price change your own trade causes by shifting the pool's reserves, and it is known before you submit. Slippage is any additional movement between quoting and execution caused by other trades; your tolerance caps how much of it you accept.
What slippage tolerance should I use?+
For liquid pairs 0.1–0.5% is common. Volatile or low-liquidity tokens may need 1–3%, and tokens with transfer taxes need more. Higher tolerance makes you easier to sandwich by MEV bots, so use the lowest value that lets the trade go through.
Why does price impact rise so fast with trade size?+
On an x·y = k curve, each extra token you sell gets a worse price than the last. Impact is roughly your trade size divided by the pool reserve plus your trade, so selling 1% of a pool costs about 1% and selling 10% costs about 9%.
How can I reduce price impact?+
Trade in a deeper pool, use a DEX aggregator that splits the order across several pools, use concentrated-liquidity pools around the current price, or break a large order into smaller trades over time.
Does this work for Uniswap v3 pools?+
Only approximately. Uniswap v3 and similar concentrated-liquidity pools behave like a constant-product pool within the active price range but with much deeper effective liquidity, so real impact is usually lower than this model suggests.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.
Sources