Payoff breakdown
| Metric | Value |
|---|
Payoff time vs collateral yield APY
Collateral and debt held at your current inputs — only the yield APY moves. Years to self-repay = debt ÷ (collateral × APY), so payoff time falls fast as yield rises.
| Yield APY | Annual yield | Years to self-repay |
|---|
The collateral pays the loan back, not you
Alchemix popularized this model: deposit ETH (or DAI) into a yield strategy, mint up to roughly 50% of that value as a synthetic debt token (alETH or alUSD), spend the borrowed funds immediately, and never send a repayment. Instead, 100% of the yield the collateral earns is redirected to your debt balance until it hits zero — at which point the position is fully unwound with no principal payment ever made by hand. The crypto loan & LTV calculator answers a different question: what does a conventional interest-bearing loan cost and when does it get liquidated. This calculator answers how long the yield itself takes to erase a debt that carries no interest rate at all — a fundamentally different mechanic, not just a cheaper version of the same one.
The math only works because debt and collateral typically share the same underlying asset. An alETH loan is backed by ETH-denominated yield, so a falling ETH price does not directly threaten solvency the way it would with a USD-denominated loan against ETH collateral — both sides move together. What still matters is the current loan-to-value against the protocol's max LTV (shown above as your buffer), and whether the yield strategy itself keeps performing; a stablecoin depeg or a yield source going to zero is the real risk, not routine price volatility.
Because the "years to self-repay" figure is just debt divided by annual yield in the same units, it also cuts both ways: raise the collateral, lower the debt, or find a higher-yielding strategy for the same collateral, and the payoff date pulls forward. The required-APY figure recalculates in your browser on every input change by solving that same equation for the APY needed to hit your target payoff year instead of your current one — useful for judging whether a stated payoff timeline is realistic against yields actually available in the market today.
FAQ
How does a self-repaying loan work (Alchemix-style)?
You deposit a yield-bearing asset as collateral (e.g. ETH routed into a staking or lending strategy) and mint a synthetic debt token against it, up to a protocol-set max LTV (Alchemix's ETH vault caps around 50%). The collateral keeps earning yield after you borrow, and 100% of that yield is automatically applied to your own debt balance instead of being paid out to you. Once cumulative yield equals the amount borrowed, the debt reaches zero on its own — no repayment transaction, no monthly payment, and (on the flagship version of the product) no interest charged, because the yield is the repayment mechanism instead of an interest rate.
How is this different from a normal crypto-backed loan calculator?
The crypto loan & LTV calculator models a conventional loan: you borrow against collateral, interest accrues on the debt over time, and you either pay that interest out of pocket or watch the debt grow. A self-repaying loan flips the direction — the collateral's own yield shrinks the debt instead of interest growing it. This calculator answers a question the conventional one can't: given this collateral, this yield rate, and this borrowed amount, how many years until the yield alone has paid the whole loan off, and how much traditional loan interest did that replace.
What happens if the yield APY drops or the collateral price falls?
A lower realized APY simply stretches the payoff timeline in this calculator's math (years to self-repay = debt ÷ (collateral × APY), so a smaller APY makes that fraction larger) — it does not create an interest charge. Collateral price risk is separate: because debt and collateral are typically denominated in the same underlying asset (ETH collateral backing an ETH-pegged debt token, for example), day-to-day price swings mostly cancel out for solvency purposes, but the position can still be liquidated if the debt token de-pegs, the yield strategy underperforms for long enough, or the current LTV (shown in this calculator) is pushed toward the protocol's max LTV by additional borrowing.
What's a realistic APY to target a specific payoff date?
This calculator solves it directly: required APY = debt ÷ (collateral × target years). For example, 4 units of debt against 10 units of collateral needs an 8% APY to fully self-repay in 5 years, but only a 4% APY to self-repay in 10 years. Compare the required APY this calculator returns against the realistic staking or vault yield available on your collateral asset — if the required APY is far above what the market actually pays, the honest payoff date is later than the target, not the target itself.