APR vs APY: why daily compounding turns the same yield into more dollars

A protocol advertises 6.5%. Another advertises 6.7%. Are they actually offering different yields?

Sometimes yes, sometimes no. Often the difference is whether the number is an APR or an APY, and once you understand the distinction, you'll notice that DeFi sometimes quotes both — usually picking whichever looks bigger.

This is the difference that makes auto-compounding strategies a meaningful feature rather than a marketing flourish. Here's the math, the intuition, and what it actually adds up to over a year.

The definitions

• APR (Annual Percentage Rate) is the simple annualized rate. If a protocol pays 6.5% APR with no compounding, $10,000 earns $650 over a year. End of story.
• APY (Annual Percentage Yield) is the rate with compounding included. If that same 6.5% is compounded daily, the actual yield over the year is higher — about 6.71%.

The formula:

APY = (1 + APR/n)^n − 1

where n is the number of compounding periods per year. For daily: n = 365. For continuous: n approaches infinity and APY = e^APR − 1.

The closer n is to continuous, the closer APY gets to its ceiling. Daily compounding captures roughly 99% of the benefit; hourly is barely distinguishable from daily.

A concrete example

Three scenarios, all starting at $10,000 and a stated 6.5% rate:

Scenario	After 1 year
6.5% APR, no compounding	$10,650.00
6.5% APR, monthly compounding	$10,669.72
6.5% APR, daily compounding	$10,671.45

Over a year on $10,000 the absolute difference looks small — about $21 between simple interest and daily compounding. Two things make it matter more than the table suggests.

First, the gap is multiplicative on principal. At $100,000 the gap is $214. At $1,000,000 it's $2,140.

Second, the gap compounds itself over multiple years. The 21 extra dollars from year one earn yield in year two, and so on. Over a ten-year horizon at constant rate, daily-compounded beats non-compounded by roughly 6% of the principal.

That is the difference between "your money grows" and "your money grows on its own growth."

Why most DeFi protocols quote APR

Lending protocols like Aave and Compound natively quote rates per second or per block. Those rates are clean APRs — the protocol does not automatically reinvest your interest for you. If you leave your deposit untouched, your underlying token balance increases through a rebasing or share-price mechanism, and you have to actively claim or restake to compound the extra balance.

Most retail users don't. They deposit once, check back in a year, and pocket the APR. That leaves real money on the table.

Why vildX quotes blended APY

Inside the vildX vault, harvests happen daily. Yield earned on each underlying position (Aave, Compound, Morpho, Curve) is collected and reinvested into the same strategy. From a user's standpoint, that means the NAV of VXUSD reflects the compounded result of every previous day's harvest.

When we quote a 5–7% target range, we're quoting APY — the number you actually realize if you hold VXUSD for a year. The underlying APRs across the four protocols are slightly lower than the headline; the compounding step closes the gap.

This is also why the headline number changes a little every week even when the underlying rates don't. As compounded NAV grows, the effective APY on the original deposit drifts up.

When compounding doesn't matter

A few honest caveats.

• Short holding periods. If you're holding for two weeks, compounding adds basis points, not dollars. Daily-vs-monthly compounding is a multi-month story.
• Volatile rates. A 7% APR that drops to 4% next month compounds to less than a steady 6%. Don't model future yield on this month's peak.
• Fees. A 6.7% gross APY net of a 1% platform fee plus a 10% performance fee is materially less than 6.7%. The number that matters to a holder is the net compounded return after fees, which is what NAV growth reflects.

Reading rates in the wild

Three habits that pay off:

1. Always ask: is this APR or APY? Headline numbers in DeFi marketing are often whichever is bigger.
2. Ask how often it compounds. Hourly vs daily is a rounding error. Daily vs monthly is real money. Monthly vs annually is significant.
3. Compare net of fees. A 6% APY net of fees is better than a 7% APY with a 2% performance fee on a strategy that fails to outperform.

Auto-compounding is one of those features that sounds boring until you do the math. Then it sounds like the reason to use a managed product instead of a manual one. For VXUSD holders, daily harvest isn't a bullet point — it's the difference between the APR you'd capture yourself and the APY you actually realize.