Utilization Rate

Every lending pool has two numbers that matter: how much is deposited, and how much of that is currently borrowed. Utilization rate is just the ratio between them. If a pool holds $10M in USDC and $8M is out on loans, utilization is 80%.

That number controls everything downstream — your yield as a lender, your borrow cost as a borrower, and whether you can actually withdraw when you want to.

How It Works

Protocols like Aave and Compound use utilization rate as the input to their interest rate models. Low utilization — say, 30% — means cheap borrowing rates and modest lender yields. The pool is flush with capital, so the protocol doesn't need to attract more.

As utilization climbs toward 80-90%, rates accelerate sharply. Most protocols have a "kink" — a target utilization point, often around 80% — where the interest rate curve bends steeply upward. Above that kink, borrow rates spike fast to pull utilization back down.

The math is straightforward. At 50% utilization, a pool might pay lenders 3% APY. At 95% utilization, that same pool might pay 18%. The rate isn't set by a committee — it's set automatically by supply and demand, recalculated every block.

Why It Matters

For lenders, high utilization means higher yield — but it also means less liquidity. If 95% of deposits are out on loans, only 5% is available for withdrawals. You might not be able to exit your position immediately.

For borrowers, high utilization means higher costs. If you opened a loan when utilization was 60% and it climbs to 90%, your variable borrow rate just jumped — automatically, with no notice.

What to Watch

The most common mistake is treating a high-yield lender position as a stable, liquid savings account. When utilization is pegged near 100%, your funds are effectively locked — other depositors have to add liquidity before you can withdraw. This isn't a bug. It's how the model works. But it catches people off guard when they need cash fast.