APY and APR

You can query latest APY and APR on chain and subgraph
All rates queried on chain or subgraph, are expressed in RAY units i.e. 10^27.
All emissions are expressed in WAD units i.e. 10^18.
APY: Compounding interest accrued by deposit or borrow on LendingPool​
APR: Non Compounding rewards earned as part of LiquidityMining​
The deposit and borrow APY displayed on the Aave front-end is compounded per second. 
Fetch Data
Subgraph
Use subgraph to query reserve data.
{
  reserves {
    name
    underlyingAsset
    
    liquidityRate 
    stableBorrowRate
    variableBorrowRate
    
    aEmissionPerSecond
    vEmissionPerSecond
    sEmissionPerSecond
    
    totalATokenSupply
    totalCurrentVariableDebt
  }
}
On-Chain
APR: getAssetData to fetch liquidity mining incentives for a/s/vToken.
APY: getReserveDatato fetch deposit and borrow rates of asset.
[, liquidityIndex, variableBorrowIndex, 
currentLiquidityRate, currentVariableBorrowRate,
currentStableBorrowRate, ,
aTokenAddress, stableDebtTokenAddress,
variableDebtTokenAddress, , ] = LendingPool.getReserveData(asset.address) 
// asset is the ERC20 supplied or borrowed, eg. DAI, WETH
​
//For stable borrows, the rate is specific to a user and can be queried through the ProtocolDataProvider contract
userStableBorrowRate = ProtocolDataProvider.getUserReserveData(asset.address, userAddress)
​
[,aEmissionPerSecond,] = IncentivesController.getAssetData(aTokenAddress)
[,vEmissionPerSecond,] = IncentivesController.getAssetData(variableDebtTokenAddress)
[,sEmissionPerSecond,] = IncentivesController.getAssetData(stableDebtTokenAddress)
​
// If the current UNIX timestamp > distributionEnd then the incentives are no longer active
distributionEnd = IncentivesController.DISTRIBUTION_END();
Compute Data
Calculate rates as👇🏻with js, python or whatever you like 😉
RAY = 10**27 // 10 to the power 27
SECONDS_PER_YEAR = 31536000
​
// Deposit and Borrow calculations
// APY and APR are returned here as decimals, multiply by 100 to get the percents
​
depositAPR = liquidityRate/RAY
variableBorrowAPR = variableBorrowRate/RAY
stableBorrowAPR = variableBorrowRate/RAY
​
depositAPY = ((1 + (depositAPR / SECONDS_PER_YEAR)) ^ SECONDS_PER_YEAR) - 1
variableBorrowAPY = ((1 + (variableBorrowAPR / SECONDS_PER_YEAR)) ^ SECONDS_PER_YEAR) - 1
stableBorrowAPY = ((1 + (stableBorrowAPR / SECONDS_PER_YEAR)) ^ SECONDS_PER_YEAR) - 1
​
// Incentives calculation
​
aEmissionPerYear = aEmissionPerSecond * SECONDS_PER_YEAR
vEmissionPerYear = vEmissionPerSecond * SECONDS_PER_YEAR
​
WEI_DECIMALS = 10**18 // All emissions are in wei units, 18 decimal places
​
// UNDERLYING_TOKEN_DECIMALS will be the decimals of token underlying the aToken or debtToken
// For Example, UNDERLYING_TOKEN_DECIMALS for aUSDC will be 10**6 because USDC has 6 decimals
​
incentiveDepositAPRPercent = 100 * (aEmissionPerYear * REWARD_PRICE_ETH * WEI_DECIMALS)/
                          (totalATokenSupply * TOKEN_PRICE_ETH * UNDERLYING_TOKEN_DECIMALS)
                          
incentiveBorrowAPRPercent = 100 * (vEmissionPerYear * REWARD_PRICE_ETH * WEI_DECIMALS)/
                          (totalCurrentVariableDebt * TOKEN_PRICE_ETH * UNDERLYING_TOKEN_DECIMALS)
​
Conversions
Both of these conversions take the input and ouput in decimal form. Multiply the output by 100 to get the percentage. 
APR -> APY
To convert the APR to APY compounded per second the formula is:
APY=(1+(APR/secondsPerYear))secondsPerYear−1APY = (1 + (APR / secondsPerYear))^{secondsPerYear} - 1APY=(1+(APR/secondsPerYear))secondsPerYear−1
APY -> APR
To convert APY compounded per second to APR the formula is:
APR=((1+APY)(1/secondsPerYear)−1)∗secondsPerYearAPR = ((1 + APY)^{(1/secondsPerYear)}  - 1) * secondsPerYearAPR=((1+APY)(1/secondsPerYear)−1)∗secondsPerYear
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Last modified 9d ago