Impermanent loss (IL) happens when you provide liquidity to an AMM pool (like Uniswap) and the price ratio of the two tokens changes compared to when you deposited. Because the pool automatically rebalances your holdings (buying the falling asset, selling the rising one), you end up with fewer of the winning token than if you'd simply held both tokens. IL becomes "permanent" only if you withdraw while the price ratio is still skewed — if prices return to their original ratio, the loss disappears. This calculator compares the value of holding your tokens vs. depositing them in a 50/50 constant-product pool (x·y=k, the Uniswap V2 model).