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A stablecoin yield calculator that returns a useful number has to do six things. Convert APR to APY using the actual compounding frequency. Strip native token incentives from real yield. Net out platform fees, withdrawal fees, and management cuts. Amortize gas across the deposit lifetime. Adjust for the holding period. Apply a tax rate appropriate to the jurisdiction. Most front-end APY badges skip four of those six steps. This guide walks through each input and ends with a $10K deposit comparison across Aave, Morpho, Sky, Coinbase, and Pendle as of May 24, 2026.
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The six inputs that turn quoted APY into net yield:

APR is the headline rate without compounding. APY is APR after compounding is applied. The formula is APY = (1 + APR/n)^n - 1, where n is the number of compounding periods per year. For a 5.00% APR compounded daily, n = 365, and APY = 5.127%. Compounded per block (12-second blocks on Ethereum, roughly 2.6 million blocks per year), the same 5.00% APR converges to about 5.127% APY as well, because at high frequencies the limit approaches continuous compounding: e^0.05 - 1 = 5.127%.
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The practical takeaway: above daily compounding, the APR-to-APY gap is nearly constant. The interesting differences come from protocols that pay rates as APY directly (Sky's SSR quotes 3.75% APY, already compounded) versus protocols that quote APR (some Curve and Convex pools display APR, requiring conversion). Always check which one the front-end is showing. Aave and Morpho dashboards quote APY by default; many liquidity-mining dashboards quote APR for the reward token and APY for the underlying.
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Three compounding cadences show up in stablecoin yield. Per-block compounding (Aave V3, Morpho Blue) accrues interest into the receipt token every Ethereum block, roughly every 12 seconds. Per-second compounding (Sky's Savings Rate, Spark) updates a rate accumulator each second; depositors see balance growth on demand. Per-epoch compounding (Ethena sUSDe) accrues yield over an 8-hour funding epoch and distributes at the epoch boundary.
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For sub-daily compounding, the APY converges to e^APR - 1. At 5% APR, that is 5.127% APY. At 10% APR, 10.517% APY. At 20% APR, 22.140% APY. The longer the time between compounding events, the slightly lower the effective APY: daily compounding at 5% APR is 5.116%, weekly is 5.066%, monthly is 5.116% as well within rounding. The takeaway is that compounding frequency matters most at high rates. At single-digit yields the gap between hourly and daily compounding is under 1 basis point. At triple-digit emissions APRs on incentive pools, compounding frequency moves the answer meaningfully.
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Real yield is paid in the deposit asset by another protocol user. A USDC supplier on Aave earns USDC interest paid by a USDC borrower. Real yield does not require selling a token to capture; the depositor can hold USDC throughout. Native yield is paid in the protocol's emissions token (CRV, BAL, AAVE, MORPHO, COMP, etc.) and is only realized when that token is sold for USDC. If the emissions token drops 30% between accrual and sale, 30% of the headline APR evaporates.
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A pool quoting 18% APY where 4% is real (borrow-demand-paid) and 14% is emissions is not the same product as a pool quoting 18% APY where 18% is real. Treat the emissions portion at a discount that reflects expected sell pressure. A common heuristic is to mark emissions yield at 40-60% of headline, depending on token liquidity and unlock schedule. For Sky's SSR, Aave V3 USDC, Morpho Blue USDC vaults (without rewards), and Coinbase USDC rewards, the entire quoted rate is real yield in USDC terms. For yield-farming pools on Curve, Convex, Velodrome, Aerodrome, and similar venues, the emissions portion is usually the majority of the rate. See the companion piece on risks of yield-bearing stablecoins for why even "real" yield can carry hidden risk.
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Three fee buckets show up in onchain stablecoin yield. Protocol reserve factor: Aave V3 takes 10-25% of borrower interest as a reserve, and the published supply APY already nets this out, so no further adjustment is needed for Aave or Morpho. Vault performance fees: MetaMorpho vaults on Morpho commonly charge a 10-15% performance fee to the curator, taken at withdrawal, and the displayed APY may or may not net this out depending on which front-end is read. Withdrawal fees: some yield-bearing tokens (older Yearn vaults, certain Beefy strategies) charge a small withdrawal fee, typically 0.1-0.5%, to discourage rapid in-and-out cycling.
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Exchange-side products have their own fee stack. Coinbase USDC rewards quote 4.7% APY in May 2026 and are net of Coinbase's spread (Coinbase keeps the difference between what it earns and what it pays). A centralized exchange that quotes a high stablecoin rate may be earning 8% and paying out 4%, keeping the rest as a margin. That structure is transparent on Coinbase (the gap is the entire business model) but opaque on smaller exchanges. The number to compare is always net yield to the depositor.
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Gas is fixed-cost; the deposit is variable. A $30 entry transaction plus a $30 exit transaction on Ethereum mainnet costs $60 round-trip. On a $10,000 deposit held one year, that is 60 basis points of yield drag. On a $1,000 deposit held one year, it is 600 basis points, more than the entire quoted yield on most platforms. On a $100,000 deposit held one year, it is 6 basis points and irrelevant.
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For sub-$10K stablecoin deposits, the dominant decision is not which protocol pays the highest APY but which chain charges the lowest gas. USDC on Base or Arbitrum costs roughly $0.05-0.30 per transaction, making round-trip gas under $1 on a $1,000 deposit (10bps). USDC on Ethereum mainnet at the same deposit size loses 6% to gas. The corollary: small deposits should default to L2 deployments (Aave V3 on Base, Morpho on Base, Spark on Base) unless the depositor specifically needs the mainnet TVL depth. Coinbase USDC rewards have zero gas on entry/exit because the position is custodied. That's a real edge for small accounts, set against the trade-off of custodial risk.
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Most jurisdictions treat stablecoin yield as ordinary income at the moment it accrues to the depositor, not when withdrawn. In the United States, the IRS has not issued definitive guidance on every yield product, but the standard interpretation (per IRS Notice 2014-21 and subsequent guidance) is that crypto income is taxable in the year received at fair market value. A 5% USDC yield held by a US taxpayer in the 32% federal bracket nets to 3.4% after federal tax, before state tax.
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Two structural differences matter for tax. Yield-bearing wrappers (sUSDS, sUSDe, sDAI) that change balance internally rather than transferring tokens may delay the taxable event until the wrapper is unwound, depending on jurisdiction and accounting method. Per-block rebasing (aTokens on Aave) is more clearly continuous income. The tax treatment of token-emissions yield is also distinct from real yield: emissions tokens are typically taxed as income at receipt and again as capital gains/losses on sale. This is jurisdiction-specific and changes; the figures in this article are pre-tax. Always confirm with a crypto-aware accountant.
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The matrix below shows what a $10,000 USDC deposit held for one year actually returns across five common venues, as of May 24, 2026. Quoted APY is the protocol headline. Net APY adjusts for fees, gas (Ethereum mainnet assumed), and emissions discounting where applicable. Dollar figures are pre-tax.
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The table flips conventional intuition. Coinbase's 4.7% rewards, despite the centralized custodian and the spread Coinbase keeps, return more on a $10K deposit than Aave V3 mainnet because the latter loses 60bps to gas. Sky's SSR looks high on paper at 3.75% but ends below Coinbase after the round-trip PSM mint and redeem. Pendle PT-USDC and Aave end roughly tied, with Pendle adding fixed-rate certainty in exchange for liquidity constraints (PT-USDC unwinds at maturity or via secondary market sale at a discount).
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For deposits 5x larger ($50K), the rankings reorder. Gas drag drops to 12bps, Aave nets 4.48%, Morpho Steakhouse nets 4.59%, Sky nets 3.63%, Coinbase stays at 4.7%, and Pendle PT-USDC nets 4.58%. At $50K, Morpho Blue overtakes Coinbase. For deposits at $1K, Coinbase dominates everything onchain because $60 of mainnet gas eats the entire year of yield.
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Eco Routes settles USDC across 15+ supported chains, including Base, Arbitrum, Optimism, Polygon, Celo, and Ethereum mainnet. For depositors comparing yield platforms across chains (Morpho on Base versus Aave on Ethereum, for example), Eco intents handle the bridge and the destination-chain gas in a single transaction, eliminating the need to hold native gas tokens on the destination. Eco is one of several USDC routing options; Circle's CCTP, Across, and LI.FI are also live. None of these change the underlying protocol APY; they affect entry/exit gas drag, which is the dominant variable on small deposits.
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APR is the annualized rate without compounding. APY is APR after compounding is applied. At 5% APR compounded continuously, APY is 5.127%. Most onchain lending front-ends (Aave, Morpho, Spark) display APY directly. Liquidity-mining dashboards often display APR for reward tokens; convert to APY before comparing.
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Coinbase USDC rewards have no gas cost on entry or exit because the position is custodied inside Coinbase. Aave V3 on Ethereum mainnet costs roughly $60 round-trip in gas, which is 60bps on a $10,000 deposit and 6% on a $1,000 deposit. For sub-$10K accounts, Coinbase's lower headline rate often nets higher than Aave mainnet, despite the centralized counterparty risk.
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Yes. Emissions yield (CRV, AAVE, MORPHO, BAL, etc.) requires selling the token to realize value, exposing the depositor to token price drift. A common discount is 40-60% of headline emissions APR depending on token liquidity and unlock schedule. Real yield paid in the deposit asset (USDC interest on Aave, SSR on Sky) does not require this conversion.
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Most jurisdictions treat stablecoin yield as ordinary income at receipt. In the United States, the IRS has indicated crypto income is taxable in the year received at fair market value. Yield-bearing wrappers like sUSDS may delay the taxable event until unwound, depending on accounting method. Consult a crypto-aware accountant; this article is not tax advice.
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For deposits under $5,000, gas drag on Ethereum mainnet usually eats the yield premium. Options that minimize gas: L2 deployments (Aave V3 on Base, Morpho on Base) or Coinbase USDC rewards (zero gas, custodial). For a $1,000 deposit held one year, Coinbase USDC at 4.7% or Aave V3 on Base at ~4.5% typically net higher than mainnet Aave.
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Sources and methodology. APY and APR rates pulled from DeFiLlama yields on May 24, 2026. Aave V3 reserve factor and per-block accrual from Aave documentation. Morpho Blue vault fees from Morpho documentation. Sky Savings Rate from Sky governance documentation. Coinbase USDC rewards rate from Coinbase USDC page. Pendle PT mechanics from Pendle documentation. Gas drag estimates assume $30 per Ethereum mainnet transaction at 15 gwei base fee. Tax framing references IRS Notice 2014-21; not tax advice. Figures refresh quarterly; APYs are variable and may have moved since publication.
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