"Yield" on a certificate of deposit refers to the APY — Annual Percentage Yield — which is the effective annual return once compounding is already factored in. It's a more complete number than a bare interest rate, and it's the one banks are required to advertise for exactly that reason.
Yield vs. a Bare Interest Rate
An interest rate (sometimes shown as APR) is the nominal rate before compounding is applied. Yield (APY) is what you actually earn over a full year once compounding is included. If a CD compounds more than once a year, its APY will always be at least as high as its stated nominal rate — the more frequent the compounding, the bigger that gap.
Calculating Maturity Value From Yield
Maturity Value = Principal × (1 + APY)^(Term in Years)
Because APY already contains the compounding effect, this formula works directly — no separate step needed to account for how often interest compounds within the year.
Comparing Yield Across Different Terms
The same APY produces very different maturity values depending on term length, since compounding needs time to build on itself. Putting $10,000 into a CD at a 5% APY:
- 3 months: matures to $10,122.72
- 6 months: matures to $10,246.95
- 1 year: matures to $10,500.00
- 2 years: matures to $11,025.00
- 5 years: matures to $12,762.82
Notice the 3-month result: it isn't exactly a quarter of the 1-year interest ($500 ÷ 4 = $125). The actual 3-month interest is $122.72 — slightly less, because compounding effects need a full year to fully play out. This is a genuinely common point of confusion when eyeballing short-term CD returns.
Compare your own CD's yield across any term
Open the CD Yield Calculator