What is Impermanent Loss? A Simple Explanation With Examples

Impermanent loss (IL) is the most misunderstood concept in DeFi. Many people become liquidity providers without understanding it, then wonder why their dollar value is lower than if they'd just held their tokens.

The Simple Explanation

When you provide liquidity to a pool (e.g., ETH/USDC on Uniswap), the pool must always maintain a 50/50 value ratio between the two assets. When the price of ETH changes, the pool automatically rebalances — selling the asset that went up, buying the one that went down.

This means you automatically sell your winners and buy your losers.

The "impermanent loss" is the difference between:

• Your current portfolio value as an LP
• What you'd have if you just held the original tokens

A Concrete Example

You deposit into a 50/50 ETH/USDC pool when:

• ETH price = $2,000
• You deposit: 1 ETH + 2,000 USDC = $4,000 total

Now ETH price rises to $3,000.

If you just held: 1 ETH × $3,000 + 2,000 USDC = $5,000

As an LP: The pool rebalanced. You now have ~0.816 ETH + ~2,449 USDC = $4,898

Impermanent loss: $5,000 - $4,898 = $102 (2.04%)

You earned trading fees during this time. If fees earned are more than $102, you net positive. If fees are less than $102, you lost money vs. holding.

IL Formula

def impermanent_loss(price_change_ratio: float) -> float:
    """
    Calculate impermanent loss given price ratio change.
    price_change_ratio: new_price / old_price
    Returns: IL as a negative percentage
    """
    r = price_change_ratio
    il = (2 * (r ** 0.5) / (1 + r)) - 1
    return il * 100

# Examples
print(f"Price doubles (2x): {impermanent_loss(2):.2f}%")    # -5.72%
print(f"Price triples (3x): {impermanent_loss(3):.2f}%")    # -13.40%
print(f"Price 5x: {impermanent_loss(5):.2f}%")              # -25.46%
print(f"Price drops 50%: {impermanent_loss(0.5):.2f}%")     # -5.72%

When IL Hurts Most

1. Correlated assets with big divergence: Providing BTC/ETH liquidity when BTC 5x's and ETH only 2x's
2. Stablecoin / volatile asset pairs: ETH/USDC is high IL risk if ETH moves a lot
3. Low fee markets: If the pool doesn't generate much trading volume, fees don't compensate

When IL Matters Least

1. Stablecoin/stablecoin pools: USDC/USDT barely moves — IL is near zero
2. Correlated pairs in similar ratios: wstETH/ETH — both track ETH price, minimal divergence
3. High-fee pools: On Uniswap v3, 1% fee pools on volatile pairs can generate enough fees to overcome IL

The "Impermanent" Part

It's called "impermanent" because if the price returns to your entry point, the loss disappears. You still have exactly 1 ETH + 2,000 USDC.

But here's the catch: most price movements are permanent. If ETH goes from $2,000 to $4,000, it rarely comes back to exactly $2,000. In practice, IL is often a permanent cost.

Strategies to Minimize IL

1. Stick to correlated pairs: ETH/wstETH, WBTC/ETH, stablecoin pairs

2. Use concentrated liquidity wisely (Uniswap v3): Higher fees in range, but more IL risk if price moves out of range

3. Calculate breakeven: Know how many days of fees you need to cover IL before entering

def days_to_breakeven(il_pct: float, daily_fee_apy: float) -> float:
    """How many days of fee income to cover impermanent loss."""
    daily_rate = daily_fee_apy / 365
    return il_pct / daily_rate

# If IL is 5.72% and daily fees are 0.1%
days = days_to_breakeven(5.72, 36.5)  # 36.5% APY = 0.1%/day
print(f"Breakeven: {days:.0f} days")  # 57 days

4. Choose pools with real volume: A Uniswap pool with $10M daily volume on $1M TVL generates ~$3,000/day in fees (0.3% fee tier) — much easier to overcome IL.

Bottom Line

Impermanent loss is real and matters. For most volatile/stablecoin pairs (ETH/USDC, SOL/USDC), you need 30-100%+ APY in fees just to break even during significant price movements.

Best use case for LP: Correlated asset pairs, stablecoin pairs, or stable low-IL Curve/Balancer pools. Avoid providing liquidity with assets you strongly believe will go up — just hold them instead.