Price impact and slippage in practice

Confusing the two leads to the most common mistake in on-chain trading: raising slippage tolerance until a transaction goes through, then treating the resulting fill as bad luck. Tolerance never reduces a cost. It only permits one.

The arithmetic, worked

All numbers below are hypothetical, chosen to make the math legible. They are not Robinhood Chain data.

Say a liquidity pool holds 10 ETH and 10,000,000 tokens. A constant-product pool keeps the product of the two sides fixed: 10 × 10,000,000 = 100,000,000. The quoted spot price is 1 ETH per 1,000,000 tokens.

Now buy with 1 ETH. The ETH side becomes 11, so the token side must fall to 100,000,000 ÷ 11 = 9,090,909.09. You receive the difference: 909,090.91 tokens. At the spot price you'd have expected 1,000,000. You got 9.09% fewer. That gap is price impact, and nobody took it from you — it is the pool repricing as you drain one side of it.

Buy with 0.1 ETH instead and the same math gives 100,000,000 ÷ 10.1 = 9,900,990.10 in the pool, so you receive 99,009.90 against an expected 100,000 — a 0.99% impact.

There is an exact shortcut for constant-product pools. If your trade is a fraction f of the pool's input-side depth, impact is f ÷ (1 + f). A trade worth 10% of the pool costs 0.1 ÷ 1.1 = 9.09%. That one line lets you size any trade before you open a wallet.

Two things to hold onto. Impact is driven by your size relative to the pool, not by the dollar amount — the same order is trivial in one pool and brutal in another. And the trading fee the decentralized exchange charges is a separate deduction on top of everything above, as is gas, paid in ETH.

Why splitting an order usually doesn't help

The standard advice is to break a large trade into smaller ones. Against price impact alone, it does nothing, and the arithmetic shows why.

Take the same pool and buy 1 ETH in two halves. The first 0.5 ETH gives 100,000,000 ÷ 10.5 = 9,523,809.52, so you receive 476,190.48 tokens. The second 0.5 ETH takes the pool to 100,000,000 ÷ 11 = 9,090,909.09, so you receive 432,900.43. Total: 909,090.91 tokens — the identical figure the single 1 ETH trade produced, and now you've paid gas twice.

What splitting genuinely buys is optionality and time. Other flow arrives between your trades, which can move the price either way. You get to look at the first fill before committing to the second. And in a pool being actively arbitraged, depth can be replenished between your tranches — that is a real effect, but it depends on other people acting, not on the split itself.

Setting slippage tolerance deliberately

Your quote is calculated at a block that has not happened yet. Between signing and inclusion, other trades can land, and slippage is the difference that creates. Tolerance is a floor on the output you'll accept: below it, the transaction reverts and you keep your funds, minus gas.

Think of it as choosing which failure you prefer. A tight tolerance means more reverted transactions and more wasted gas, but no surprise fills. A wide tolerance means the trade almost always executes, and on a thin or fast-moving pool it can execute far from the quote. Neither setting makes a trade cheaper; the pool's depth does that.

Two practical notes. Setting a wide tolerance on a shallow pool is what turns a bad trade into a memorable one, because there is little depth to absorb whatever lands ahead of you. And if a transaction reverts repeatedly no matter the tolerance, the cause is usually not slippage at all — I can't sell my token separates the settings problems from the contract problems.

Reading depth before you trade

On Robinhood Chain, liquidity lives largely in Uniswap v3 positions, where liquidity is concentrated into price ranges rather than spread across the whole curve. The constant-product math above is the right mental model and the wrong precise number: inside a dense range, real impact is lower than the table suggests; once price exits that range, it can be sharply worse. Trust the interface's quoted impact figure over any formula, and use the formula to know when a quoted figure deserves suspicion.

Before sizing a trade, read the pool's actual depth on the token page, and compare tokens on that field in the screener or across trending tokens when you're choosing between candidates. The three-check habit before any purchase is in how to buy tokens safely on Robinhood Chain, the exit side is in sell tokens and cash out, and when the read is done you can buy tokens on Robinhood Chain.

Frequently asked questions

Nothing on Locksley is a recommendation to buy, sell or hold, and no page here knows your circumstances.