Crypto Slippage Calculator

Crypto Slippage Calculator

During the 2021 DeFi summer, it was common to see Uniswap v2 swaps under $10,000 lose 3 to 5 percent at execution on low-cap tokens. The trade went through, the wallet showed a new balance, and the only way to actually see what slippage cost was to open Etherscan and compare expected output to actual output, line by line.

This calculator won't prevent any of that. Nothing does, once the transaction is signed. What it does is let you measure slippage cleanly after the fact, in dollars and percent, so you actually know what DEX trading is costing you across hundreds of swaps.

How slippage actually shows up on a DEX

Slippage on a DEX has two sources, and most explanations conflate them. There's price impact, where your trade itself moves the price. The bigger your swap relative to the pool size, the more you push the curve against yourself. This isn't a glitch, it's how AMMs are designed to work.

Then there's execution slippage, which happens between the moment you sign the transaction and the moment it's mined. Other people trade in the meantime, liquidity shifts in or out of the pool, and by the time your transaction lands the pool isn't where it was when your wallet calculated the quote.

Most interfaces lump these together under "slippage tolerance" because users don't want to learn the difference. But it matters when you're trying to figure out why a trade cost more than expected. Price impact you can predict before signing. Execution slippage you can only measure after.

The calculator above measures both, combined, after the trade. Enter the expected execution price your wallet quoted, the price the trade actually settled at, and the trade size. It tells you the gap in actual dollars rather than in basis points or as some abstract fraction of your slippage tolerance setting.

What this calculator does, and what it doesn't

Worth being clear about scope, because most slippage calculators online are actually price impact estimators that pretend they're measuring the same thing.

This calculator is a post-trade analyzer. You feed it numbers from a transaction that already happened and it tells you what slippage actually cost. It doesn't predict slippage on a future trade. For that, you want the quote your DEX router gives you before you sign.

Uniswap shows the expected price impact directly in its swap interface. 1inch's aggregator goes further with route-level estimates across multiple liquidity sources. CoW Swap takes a different approach entirely by batching trades together to remove most slippage from the equation.

What this is good for: looking at a week of swaps and figuring out which ones actually went smoothly versus which ones bled value at execution. That's a hindsight tool, and hindsight is exactly what most traders skip when they're chasing the next entry.

The slippage tolerance setting most people get wrong

Most DEX interfaces ship with 0.5 percent slippage tolerance as the default. For stablecoin swaps that's wildly too high. For volatile altcoins it's often too low.

For stablecoin pairs in deep pools, 0.1 percent is usually enough. Anything above 0.3 percent on a USDC-USDT swap means something weird is happening with the route.

For blue-chip liquid tokens like ETH, BTC, or major L1s on a high-liquidity pool, 0.3 to 0.5 percent works for normal market conditions. During fast-moving days, bump it up.

For low-cap or thin-liquidity tokens, 1 percent minimum, often 2 to 3 percent. If you need above 5 percent for a token to trade at all, that's a signal about the token, not about your settings.

Reading the result without fooling yourself

The calculator gives you three numbers: the total price deviation, the slippage loss in dollars, and the slippage as a percent. The dollar figure is usually the one that matters most.

Take a trader who runs about $180,000 of swap volume in a year, with average slippage running close to 0.45 percent. That's roughly $810 in execution costs across the year, before counting gas. On a $25,000 trading account, that's a 3.2 percent annual drag on capital that never shows up on a P&L statement because each individual trade looked fine. The dollar figure forces you to see it. The percent figure on a single trade lets you ignore it.

Where this gets useful in practice is when you log a few weeks of trades and run them through the calculator. Patterns emerge. Maybe your worst slippage hits cluster around the same hour of day, when liquidity providers are pulling out before US market open. Maybe a specific token consistently costs you more than expected because the main pool has fragmented across two DEXes.

When this calculator stops being useful

Two scenarios where this isn't the right tool.

If you're about to trade large size on a token with patchy liquidity, the post-trade view is the wrong shape of analysis. You want the route quote before you sign, and an aggregator handles that better than any standalone calculator.

Conventional advice says to just bump up your slippage tolerance and let the trade through. That's bad advice. Higher tolerance doesn't get you a better price, it just makes you a more attractive target for sandwich bots. A more honest fix is to split a large swap into smaller chunks, which is essentially what dollar-cost averaging does for entries.

The other situation is liquidity provision. If you're farming or analyzing a pool's behavior over time, slippage is one variable in a bigger picture. Impermanent loss interacts with execution costs in ways most LPs underestimate. Use the impermanent loss calculator alongside this one for the full picture.