APY vs APR

What Are APY and APR?

APY (Annual Percentage Yield) and APR (Annual Percentage Rate) are two ways of expressing interest rates on an annualized basis. The core difference is whether compounding is factored into the calculation. APR states the raw periodic rate scaled to one year, treating interest as simple: you earn (or owe) interest only on the original principal. APY accounts for compound interest, where earned interest is added to the principal and itself begins generating returns.

In traditional finance, lenders advertise loans using APR (making borrowing costs look lower), while banks advertise savings accounts using APY (making returns look higher). In crypto and DeFi, the same dynamic plays out: protocols choose whichever metric paints the most attractive picture for their product.

How They Work

APR is straightforward: if a protocol offers 10% APR on a deposit of $1,000, you earn $100 in interest over one year, regardless of how often interest is paid. The interest does not compound.

APY incorporates compounding: interest earned in each period is added to the principal, so subsequent periods generate interest on a larger balance. The more frequently interest compounds, the higher the effective annual return.

The Compounding Formula

The formula to convert APR to APY depends on the number of compounding periods per year:

APY = (1 + APR / n)^n - 1

Where:
  APR = annual percentage rate (as a decimal, e.g. 0.10 for 10%)
  n   = number of compounding periods per year

Examples:
  Monthly compounding:   APY = (1 + 0.10/12)^12 - 1  = 10.47%
  Daily compounding:     APY = (1 + 0.10/365)^365 - 1 = 10.52%
  Continuous compounding: APY = e^APR - 1              = 10.52%

When compounding happens only once per year (n = 1), APY equals APR exactly. As the compounding frequency increases, APY grows: but the gains diminish rapidly beyond daily compounding.

Compounding Frequency Comparison

The following table shows how the same 10% APR translates to different APY values depending on compounding frequency:

At lower APR values the difference is even smaller. For a 5% APR compounded monthly, the APY is 5.12%: a gap of just 0.12 percentage points. At higher rates the gap widens: 50% APR compounded daily yields an APY of roughly 64.8%.

APY and APR in DeFi and Crypto

In decentralized finance, APY and APR appear across virtually every product that involves earning or paying interest. Understanding which metric a protocol is displaying is critical to evaluating real returns.

Staking

Proof-of-stake networks reward validators and delegators with new tokens for securing the network. Staking rewards are typically quoted in APR because the rewards must be manually claimed and restaked (compounded) by the user. Some platforms offer auto-compounding, where smart contracts automatically restake earned rewards. In those cases, the effective return is closer to APY.

The distinction matters: a protocol advertising 8% staking APY with auto-compounding delivers a different outcome than one advertising 8% APR where rewards sit idle until manually restaked.

Yield Farming

Yield farming involves depositing tokens into liquidity pools or vaults to earn trading fees and token rewards. Protocols commonly display APY because many vaults auto-compound: they harvest reward tokens, sell them, and reinvest the proceeds on each blockchain block or at regular intervals.

The advertised APY assumes that compounding continues at the current rate for a full year. In practice, rates change constantly as liquidity enters or leaves the pool, as token prices fluctuate, and as reward emissions decrease over time.

Lending Protocols

Lending protocols display both APR and APY depending on context. Borrowing costs are often shown as APR (the cost before compounding), while supply rates may be shown as APY (the return after compounding). On many Ethereum-based lending platforms, interest accrues every block (roughly every 12 seconds), which means the compounding frequency is extremely high: but at typical DeFi lending rates of 2% to 8%, the difference between APR and APY is minimal.

Stablecoin Yield

Stablecoin yield products let users earn returns on dollar-pegged assets. Because stablecoins maintain a roughly constant price, the APY figure more accurately represents real purchasing-power returns compared to volatile tokens. Sustainable stablecoin yields on established platforms in 2026 typically range from 3% to 8% APY, sourced from lending demand, real-world asset backing, or treasury bill returns.

For a deeper look at how stablecoin yield products work and the regulatory landscape around them, see the stablecoin yield landscape and yield-bearing stablecoins research articles.

Why It Matters

Comparing opportunities using different metrics leads to bad decisions. A protocol offering 12% APY and another offering 12% APR are not equivalent: the APR-quoted product may deliver higher real returns if you compound manually at a favorable frequency, or it may deliver lower returns if you never compound at all.

When evaluating DeFi yield opportunities, always normalize to the same metric before comparing. Convert APR to APY using the compounding formula above, or convert APY to APR by reversing it:

APR = n * ((1 + APY)^(1/n) - 1)

Where:
  APY = annual percentage yield (as a decimal)
  n   = number of compounding periods per year

In the broader Spark ecosystem, USDB offers yield-bearing stablecoin functionality where understanding the difference between quoted APR and effective APY helps users accurately project their returns.

Risks and Considerations

Misleading APY Displays

Some DeFi protocols inflate their displayed APY by assuming unrealistic compounding conditions. A protocol might calculate APY based on the current instantaneous rate, extrapolate it over a full year, and assume continuous compounding: even though the rate could change in minutes. An APY that is computed from a single day's performance can look dramatically different from the actual annualized return.

Extremely high APY figures (100% or above) are typically a red flag. These rates often come from inflationary governance token emissions: the protocol prints new tokens to subsidize yields. As more users deposit and the token's price drops from selling pressure, the realized return shrinks far below the advertised number.

Token Price Depreciation

When rewards are paid in a volatile token rather than the deposited asset, APY can be deeply misleading. A 50% APY paid in a governance token that loses 60% of its value over the year results in a net loss. This is distinct from impermanent loss (which affects liquidity providers specifically) but compounds with it when both factors are present.

Stablecoin-denominated yields avoid this problem because the reward and the deposit share the same unit of account. This is one reason stablecoin yield rates are more reliable indicators of real return.

Variable Rates

Most DeFi interest rates are variable: they change based on supply and demand within the protocol. A lending pool at 10% APY today may drop to 2% tomorrow if a large amount of new capital enters the pool. The advertised APY is a snapshot, not a guarantee. Over weeks and months, the effective return can differ substantially from the rate displayed at the time of deposit.

Gas Costs and Compounding

On networks with significant transaction fees, the cost of compounding can erode returns. If claiming and restaking rewards costs $5 in gas fees and the reward per period is $3, compounding more frequently actually reduces net returns. This is why auto-compounding vaults and yield aggregators batch transactions across many users: spreading the gas cost makes frequent compounding economically viable.

This glossary entry is for informational purposes only and does not constitute financial or investment advice. Always do your own research before using any protocol or technology.