What Is Impermanent Loss?

Impermanent loss is the gap between what your tokens would be worth if you simply held them versus what they are worth after sitting in a liquidity pool. It is one of the most misunderstood risks in DeFi, so let's break it down with plain math and a concrete example.

What impermanent loss actually means

Impermanent loss (IL) is the difference in value between two choices: depositing two tokens into a liquidity pool versus just keeping those same tokens in your wallet. When the price ratio of the two tokens changes after you deposit, the pool rebalances your holdings automatically, and you can end up with less total value than if you had done nothing.

It is called "impermanent" because the loss only becomes real when you withdraw. If prices drift back to where they started, the gap can shrink or disappear. But if you withdraw while prices are far apart, the loss is locked in and very much permanent.

To understand IL, you first need to understand how a basic DeFi liquidity pool works. Most decentralized exchanges use an automated market maker (AMM) running on smart contracts. A common design keeps the product of the two token balances constant (the "x times y equals k" formula). When traders buy one token from the pool, its balance drops and the other rises, keeping the math balanced. You, as a liquidity provider, own a share of whatever is in the pool at any moment.

Why providing liquidity can underperform holding

Here is the core problem. When one token in your pair rises sharply in price, arbitrage traders buy it out of the pool until the pool's price matches the open market. That means the pool sells your appreciating token cheaply and leaves you holding more of the token that did not move. You captured less of the upside than a simple holder did.

• If both tokens move together (same direction, same percentage), the ratio stays constant and there is no impermanent loss.
• If the ratio diverges, IL appears. The bigger the divergence, the bigger the loss versus holding.
• Trading fees offset IL. Liquidity providers earn a cut of every swap. In active pools, accumulated fees can exceed the impermanent loss, leaving a net gain.

So the real question is never "IL or no IL." It is whether the fees (and any reward incentives) you collect outweigh the loss from price divergence over your holding period.

The simple math

For a standard 50/50 pool, impermanent loss depends only on the price ratio change between the two tokens, not on the absolute prices. If one token's price changes by a factor r relative to the other, the loss versus holding can be approximated by a fixed schedule. The table below shows the well-known reference figures.

Notice that the loss is symmetric: a token falling to half its relative price produces the same percentage IL as it doubling. Notice also that small price moves cause almost no IL, while large moves bite hard. This is why stablecoin pairs (whose prices barely diverge) carry very little impermanent loss, while volatile pairs carry a lot.

A worked example

The example uses crypto-style volatile assets to make the effect visible. Plug in a stablecoin pair where neither side moves much and the loss shrinks toward zero.

When impermanent loss matters (and when it doesn't)

IL is not always a dealbreaker. Whether it matters depends on the pair you choose and how long you stay in.

Beyond the math, keep these practical points in mind:

• Fees and rewards can win. High-volume pools often pay enough in swap fees to beat IL. Always compare expected fees against expected divergence.
• Time horizon matters. Prices can return to the starting ratio, erasing IL. Short, sharp moves you wait out hurt less than permanent re-pricings you withdraw into.
• Other risks stack on top. Smart-contract bugs, exploits, and scam pools are separate dangers. Review our guide on how to avoid crypto scams before committing funds, and use a secure setup from our crypto wallet types overview.
• Gas costs add up. Entering, exiting, and claiming rewards all cost transaction fees — see what is a gas fee — which can erode small positions.

Some platforms advertise "no IL" or one-sided liquidity options. These typically shift the risk elsewhere (to the protocol, to a counterparty, or into lockups) rather than removing it. Read the mechanism carefully and never assume a higher advertised yield is free of trade-offs.

Key takeaways

• Impermanent loss is the underperformance of pooled tokens versus simply holding them, driven by price divergence.
• It depends on the price ratio change, is symmetric up and down, and grows fast for large moves.
• Trading fees and incentives can offset or exceed IL — the net outcome is what counts.
• Stable and correlated pairs carry little IL; unrelated volatile pairs carry the most.
• IL becomes permanent only when you withdraw at a diverged price.

Providing liquidity can be a reasonable way to earn yield, but it is not the passive, risk-free income it is sometimes made out to be. Understand the pair, model the fees against likely divergence, and size your position conservatively. This article is educational and is not investment advice; do your own research and only commit funds you can afford to lose.