Health Factor

What Is Health Factor?

Health factor is a numerical metric used by DeFi lending protocols to represent the safety of a borrower's collateralized position. It expresses the ratio between the value of a user's deposited collateral (adjusted by liquidation thresholds) and their outstanding debt. A health factor above 1 indicates a solvent position, while a health factor at or below 1 signals that the position is eligible for liquidation. For anyone borrowing in DeFi, the health factor is the single most important number to monitor.

How Health Factor Is Calculated

The standard health factor formula used by most lending protocols is:

Health Factor = (Total Collateral Value x Weighted Liquidation Threshold) / Total Borrowed Value

Each collateral asset has its own liquidation threshold, which represents the maximum percentage of collateral value that can be borrowed against before the position becomes liquidatable. For example, if ETH has a liquidation threshold of 82.5%, then $10,000 worth of ETH collateral contributes $8,250 to the numerator of the health factor calculation.

If a borrower has deposited multiple collateral assets, the calculation uses a weighted average of their liquidation thresholds. The denominator is the total value of all outstanding debt, including accrued interest.

Here is a concrete example: A user deposits $10,000 in ETH (liquidation threshold 82.5%) and borrows $4,000 in USDC. Their health factor would be ($10,000 x 0.825) / $4,000 = 2.06. This means the collateral value would need to drop by roughly half before the position faces liquidation.

What Different Health Factor Values Mean

Understanding the practical implications of different health factor ranges helps borrowers manage risk:

• Above 2.0 — A comfortable buffer. The position can absorb significant market volatility before approaching liquidation. Conservative borrowers typically aim to maintain a health factor in this range.
• 1.5 to 2.0 — Moderate risk. The position has a reasonable safety margin, but sharp market movements could threaten it. Active monitoring is advisable.
• 1.0 to 1.5 — Elevated risk. The position is approaching the liquidation zone. Borrowers in this range should consider adding collateral or repaying debt immediately.
• At or below 1.0 — The position is liquidatable. Third-party liquidators can repay a portion of the debt and claim collateral at a discount (the liquidation bonus). The borrower loses collateral and may still owe residual debt.

What Causes Health Factor to Change

Health factor is a dynamic metric that shifts constantly as market conditions change:

• Collateral price drops — If the market value of deposited collateral falls, the numerator decreases and the health factor drops. This is the most common cause of liquidations, particularly during sharp market downturns.
• Debt value increases — If a borrower has borrowed a volatile asset that appreciates in value, the denominator increases. This is particularly relevant for borrowers who take out loans denominated in volatile tokens rather than stablecoins.
• Interest accrual — Borrowing rates continuously add to the outstanding debt, gradually reducing the health factor over time, even if market prices remain stable.
• Collateral price increases — Rising collateral values improve the health factor, giving borrowers more breathing room.

Strategies for Managing Health Factor

Experienced DeFi borrowers use several strategies to maintain a healthy position:

• Add more collateral — Depositing additional assets into the position directly increases the numerator and improves the health factor.
• Repay a portion of the debt — Reducing the borrowed amount decreases the denominator, boosting the health factor. This is often the fastest way to move out of a danger zone.
• Choose stable collateral — Using less volatile collateral assets (or diversifying across multiple assets) reduces the likelihood of sudden health factor drops.
• Set alerts — Many DeFi dashboards and third-party tools allow users to set notifications when their health factor drops below a specified threshold, enabling timely action.
• Use conservative loan-to-value ratios — Borrowing well below the maximum allowed amount creates a larger buffer against market volatility.

Lending aggregators display health factor prominently when comparing lending options, helping borrowers understand the risk profile of each position before committing collateral.

Health Factor Across Different Protocols

While the concept of health factor is universal across DeFi lending, the specific parameters vary by protocol and asset. Aave, Compound, and Morpho each set their own collateral factors and liquidation thresholds, meaning the same collateral-to-debt ratio can result in different health factors depending on where you borrow. Understanding these differences is essential for optimizing position safety across protocols.

Health factor is not merely a technical metric — it is the borrower's most direct connection to the risk of their position, and managing it effectively is one of the most important skills in DeFi lending.