What is impermanent loss? A plain guide for liquidity providers

Impermanent loss is the money a liquidity provider gives up when the prices of pooled tokens move apart after you deposit them. It is the gap between two things. The value of your share in the pool, and the value of simply holding the same coins in your wallet. There is no hack here. The pool is working exactly as designed, and that is the point worth understanding before you add a single dollar to one.

Why liquidity pools create the loss

Most decentralized exchanges run on a simple rule called the constant product formula, written as x times y equals k. The letters x and y stand for the amounts of the two tokens in the pool. The letter k is a number that has to stay the same after every trade. When traders swap one token for the other, the pool adjusts the amounts to keep k fixed, and that changes the price the pool quotes. A larger swap shifts that quoted price more, an effect traders call slippage.

This is the engine behind an automated market maker. When the outside market price of a token moves, traders and arbitrage bots step in. They buy the cheap side of the pool and sell the expensive side until the pool price matches the wider market. That trading is good for the exchange. It is also what quietly shifts the mix of tokens you own inside the pool.

Here is the catch. The pool always ends up holding more of the token that fell in price and less of the token that rose. You wanted to keep the winner. The formula sold it for you on the way up. It works a little like a shop forced to keep its shelves half stocked with two goods. When one good jumps in value, the shop has already sold some of it cheap to stay balanced. That forced rebalancing is the root of impermanent loss.

A worked example with real numbers

Say you deposit 1 ETH and 1,000 USDC into a pool when 1 ETH trades at 1,000 USDC. Your stake is worth 2,000 USDC. Imagine the whole pool holds 10 ETH and 10,000 USDC, so k equals 100,000 and you own 10 percent of it. Both sides are worth the same at the start, which is how these pools are meant to begin. Nothing unusual yet.

Now ETH doubles on the open market to 2,000 USDC. Arbitrage traders rebalance the pool until it holds about 7.071 ETH and 14,142 USDC. Your 10 percent share is now 0.7071 ETH and 1,414.2 USDC. Add that up at the new price and it comes to 2,828.4 USDC.

Not bad. Your deposit grew. But if you had just held the original 1 ETH and 1,000 USDC in your wallet, you would have 3,000 USDC. The difference is 171.6 USDC, or about 5.7 percent. That 5.7 percent is the impermanent loss, and the figures here follow the worked example published by Chainlink.

How deep the loss gets

The size of impermanent loss depends only on how far the two prices drift apart, not on the direction. A small move barely registers. A large one bites. Ledger Academy gives the standard estimate as impermanent loss equals 2 times the square root of the price ratio, divided by 1 plus the price ratio, minus 1.

Run that formula and a clear pattern appears. A price change of 1.25 times costs about 0.6 percent. A 1.5 times move costs 2 percent. A doubling, as above, costs 5.7 percent. A tripling costs 13.4 percent. A fourfold move costs 20 percent, and a fivefold move costs 25.5 percent. Chainlink lists the same 0.6 percent and 25.5 percent at the ends of that range.

Notice the shape. The loss is small at first, then grows faster as the prices separate. It never turns into a total wipeout from price movement alone. A token can still fall to zero, but that is a different risk and not what impermanent loss measures.

Direction does not matter either. Had ETH halved to 500 USDC instead of doubling, the same formula returns the same 5.7 percent. A pool punishes any wide gap between the two prices, up or down. That is the single most useful thing to remember. It is why a pair of two assets that move together is far safer than a jumpy token sitting next to a steady one.

Why it is called impermanent

The loss only exists on paper while the price gap is open. If the two prices drift back to where they started, the gap closes and the loss disappears. That is the hopeful part of the name. You are not down anything until you act.

But the word impermanent oversells it. The moment you withdraw your tokens, the loss becomes real and permanent. Prices do not always come back. Many liquidity providers pull out during a sharp move, lock in the gap, and only then learn what it cost them. Some researchers prefer the plainer term divergence loss, because that is what it really is.

Why anyone provides liquidity at all

If the pool keeps selling your winners, why do people line up to supply it? Fees are the short answer. A provider earns a slice of every trade that passes through the pool, and on a heavily used pair those slices add up quickly. The bet is simple. Earn more in fees than you give up to divergence, and you walk away ahead.

Protocols often sweeten the deal with extra token rewards on top of the fees. That can tip a losing position into a winning one, at least while the rewards last. It can also hide the impermanent loss underneath, which is how some providers finish a year holding fewer dollars than they started with, even after a cheerful dashboard showed steady yield the whole time. Read the fee income and the reward schedule as two separate things.

Put the numbers next to something plain. A 5.7 percent loss on a 10,000 dollar position is 570 dollars. If that pool charged 0.3 percent on every swap and churned through its full size a few times a week, the fees might cover the 570 dollars in a month or two. If the trading dried up, they would not. The loss is fixed by the price move. The fees are a race against it.

How providers try to limit it

Trading fees are the first defense. Every swap in the pool pays a fee to liquidity providers, and over time those fees can cover the impermanent loss and leave a profit. Whether they do depends on how much the pool trades and how wild the prices get. In a calm, busy pool the fees often win. In a quiet pool during a violent price move, they often do not.

A second defense is picking the right pair. Pools made of two assets that track each other closely, such as two dollar stablecoins or two staked versions of the same coin, barely diverge, so the loss stays tiny. This is why stablecoin pools are the busiest corner of DeFi. Newer designs, such as concentrated liquidity and single sided pools, also try to reshape the risk, though none of them delete it.

There is no setting that removes impermanent loss while keeping the fee income. Anyone who promises that is selling something. The honest framing is a trade. You accept the risk of divergence in return for a cut of the trading fees.

What to check before you add liquidity

Check how closely the two tokens track each other. The further they can drift apart, the larger your potential impermanent loss. A volatile token paired with a stablecoin is the classic high risk setup, because one side can run while the other sits still. Correlated pairs, such as two versions of the same staked asset, keep that gap narrow by design and so keep the loss near zero.

Then look at the fee income the pool actually earns, not the headline yield a dashboard shows. A high advertised return often hides heavy impermanent loss underneath. Model a few price scenarios with the formula above before you commit. And remember what the number leaves out. Impermanent loss says nothing about smart contract bugs, a token that collapses, or a pool that gets drained. Those are separate risks, and they have ended more liquidity positions than price divergence ever has.