Price impact and slippage for a buy on the Pump.fun bonding curve
Price impact is how much your own buy moves the price. Slippage tolerance is how much worse than the quoted price you are willing to accept before the transaction is rejected. They are related but not the same: impact is caused by your trade, slippage also covers other trades that land before yours.
This calculator uses the Pump.fun bonding curve formula, so the impact it shows is what the curve itself would charge for your buy at the market cap you enter.
A Pump.fun coin starts with virtual reserves of 30 SOL and about 1.07 billion tokens, and every trade keeps their product constant. The more SOL is already in the curve, the less your buy moves the price — which is why the same 0.5 SOL has a large impact on a brand-new coin and a small one later.
On this curve the average price you pay is higher than the starting price by your buy divided by the SOL in the curve. The price right after your buy rises by roughly twice that.
Set it a little above the price impact you expect, plus room for other buys landing first. On a fresh launch prices move fast, so tolerances of 10–20% are common; on a calm coin a few percent is enough.
A higher tolerance makes the buy more likely to go through but lets you pay more — and gives bots more room to trade around you. Do not raise it further than you need.
Enough to cover your own price impact plus normal movement. For brand-new coins that is often 10–20%; for older, calmer coins much less. Use the calculator to see your impact first.
The price moved more than your tolerance between quoting and landing — usually because other buys landed first or your own buy was large relative to the curve. Raise the tolerance slightly or buy less.
Price impact is the move caused by your trade alone. Slippage tolerance is the total worse-than-quoted price you accept, including moves caused by other traders.
No. After graduation the coin trades in a PumpSwap pool, where impact depends on that pool's liquidity. The calculator models the bonding curve only.