Syncswap minimum received is the quoted output minus your slippage allowance, passed to the router as amountOutMin; if execution produces less, the transaction reverts.
Syncswap is the multi-pool DEX where that floor is set before the transaction is signed.
You are checking a swap in MetaMask Wallet and the screen says 1,000 USDC expected, 995 USDC minimum received. That second number is not a forecast of what the market will do. It is the transaction’s condition: accept at least 995, or execute nothing.
The three numbers that matter
The calculation is simple once the figures are separated.
- Quoted output: 1,000 USDC, already calculated from the selected route and pool fees.
- Slippage setting: 0.50%, meaning the allowed reduction is 5 USDC.
- Minimum received: 995 USDC, calculated as 1,000 × (1 − 0.005).
The number is denominated in the output token, not in dollars and not in the input token. If the quote is for ETH, the minimum is an ETH amount. Gas paid separately through the L2’s native token does not reduce it.
What Syncswap calculates before the transaction
First, the route calculator estimates the output from each pool, including price impact and the pool’s trading fee. In a Classic Pool, the familiar constant-product calculation is used:
amountOut = (amountIn × (100,000 − fee) × reserveOut) ÷ (reserveIn × 100,000 + amountIn × (100,000 − fee))
The 100,000 denominator represents 100% in the contract’s fee scale. The result is rounded down in token units. The fee is therefore part of the quote; it is not an extra deduction that mysteriously appears after the minimum is calculated.
Syncswap’s router then turns the route into execution steps. It prefunds the first pool, passes intermediate output into the next pool when there is another hop, and adds the final output from split paths. Only after those steps does it compare the accumulated amount with amountOutMin. If the result is smaller, the router raises TooLittleReceived and the whole swap reverts.
That distinction matters. The quote can fall because the pool itself moves when your trade enters it; that is price impact. It can also fall because another transaction changes the pool before yours executes; that is execution slippage. Minimum received protects against the second problem and limits how much of the first you are willing to tolerate after the quote.
Why the old x*y=k advice is incomplete
The older shortcut—“Syncswap uses the constant-product formula”—is no longer a safe description of the current exchange.
Syncswap’s newer multi-pool design includes Classic, Stable, Aqua and Range models. Stable Pools use a hybrid curve for assets that should trade near parity, much like the design ideas associated with Curve Finance. Aqua Pools use a Curve v2-style two-crypto model with automated concentration and dynamic fees. Range Pools use chosen price bands rather than infinite-range Classic liquidity.
The final protection is still the same integer threshold, but the quoted output feeding it is model-specific. A dynamic Aqua fee can change as the pool becomes unbalanced. A Range Pool can have less usable liquidity once price leaves its active band. That is why copying a fixed fee or a Classic formula into a spreadsheet can produce a plausible-looking minimum that does not match the transaction.
How to choose the setting
Use the smallest tolerance that gives the trade a realistic chance of landing.
- Check the route and the pool type, not only the headline exchange rate.
- Separate price impact from the slippage tolerance you are about to approve.
- For a volatile or thin pair, consider a smaller trade or a refreshed quote before increasing tolerance.
- Remember that a reverted transaction can still consume gas, even though the token swap does not settle.
- After execution, compare the received token amount with the minimum and inspect the route, not just the dollar value.
Ethereum Mainnet provides the settlement security behind the rollup environment, but the pool state and router call are on the supported Layer 2. A Mainnet gas assumption does not change the minimum received figure.
FAQ
Can I receive more than the minimum? Yes. Minimum received is a floor, not a promised final amount.
Does 0.50% mean the trade loses 0.50%? No. It permits execution up to 0.50% below the current quoted output; the actual result may be better.
Why did the minimum change without changing my setting? The route, pool balances, dynamic fee or quoted output changed.