When you are choosing where to save, compare deposit APY with deposit APY. When you are comparing similar loans, compare their disclosed APR and the payment terms. A savings account’s nominal interest rate, its APY, and a loan’s APR answer different questions; one conversion formula cannot make loan APR and deposit APY interchangeable.
Under the federal Truth in Savings definitions, deposit APY reflects interest paid over a 365-day period based on the interest rate and compounding frequency. The deposit interest rate is the annual rate before compounding. A loan APR instead measures the cost of credit. The CFPB explains for auto loans that APR includes the borrowing interest rate plus applicable lender fees, such as origination charges.
Read the right number for the decision
| Figure | What it describes | Use it to |
|---|---|---|
| Deposit APY | Annualized deposit interest including compounding under disclosure assumptions | Compare deposit yields alongside fees, access, and rate conditions |
| Deposit interest rate | Annual stated rate on the deposit before compounding | Understand how the institution states the rate; check compounding and balance rules |
| Loan APR | Annualized credit cost reflecting the loan’s interest and certain charges | Compare comparable borrowing offers with their terms and total payments |
There is a labeling wrinkle: the deposit regulation permits an institution to also call its noncompounded deposit interest rate an “annual percentage rate” in certain account disclosures. Read the surrounding account context. That deposit-rate label is not the borrowing APR on a car loan or mortgage.
A deposit example with all assumptions visible
Hypothetical math, not a current bank offer: Put $1,000 in an account for one 12-month illustration with a 2.00% nominal annual deposit interest rate, monthly compounding, no deposits or withdrawals, and an unchanged rate. Ignoring fees and taxes, the idealized calculation is $1,000 × (1 + 0.02 ÷ 12) to the 12th power, or about $1,020.18 at year end. Interest is about $20.18; the implied annual yield is about 2.0184%, a little above the 2.00% nominal rate because interest earns interest.
This example uses twelve equal compounding periods as a teaching model, not a prediction of bank-accurate cents. Actual account agreements can use different day counts, balance methods, crediting schedules, rate tiers, and rounding. The CFPB’s APY calculation rules also assume principal and interest stay on deposit, with no other transactions, for the disclosure term. A changing variable rate, a midyear deposit, or fees means your realized dollars can differ from a one-year APY illustration. See how a month’s savings interest depends on balance and timing.
Why you cannot turn loan APR into savings APY
The monthly-compounding expression above connects one specified deposit interest rate to a hypothetical deposit yield. It does not calculate a loan APR. The federal credit APR rule relates the amount and timing of funds received to the amount and timing of payments; loan charges and transaction structure matter. Without the actual loan disclosures, there is no defensible single APR-to-APY conversion that tells you what a savings account earns or what a loan costs in dollars.
For example, if two hypothetical auto-loan quotes show the same stated interest rate but different APRs, ask what financed fees and other terms account for the difference. Do not assume that the APR difference alone gives a monthly payment or total cost. Compare the same loan amount and term, then inspect financed amount, payment schedule, fees, and total of payments in each disclosure. The CFPB cautions against comparing an auto-loan APR with another loan’s interest rate.
A quick comparison before you choose
- Saving: Compare APYs for accounts meeting your balance and eligibility conditions, then check maintenance fees, access, and whether the rate can change. The FDIC notes APY helps compare deposit products but does not compare CD early-withdrawal penalties.
- Borrowing: Compare disclosed APRs only across relevant loan offers and inspect term, payments, and charges. A lower APR with a longer term need not mean fewer dollars paid overall.
- Near-term money: If funds are for a known bill or emergencies, access and timing can matter more than a small hypothetical yield difference. Start with your bill deadline or emergency cash need.
Next time a rate catches your eye, write down what product it belongs to, whether it is APY, nominal deposit interest, or loan APR, and which assumptions and fees accompany it. Compare matching measures first, then decide whether the account’s access or loan’s payment schedule fits the actual purpose.
Sources and notes
- eCFR, 12 CFR 1030.2 deposit rate definitions
- CFPB, Appendix A to Regulation DD
- CFPB, Loan interest rate versus APR
- eCFR, 12 CFR 1026.22 credit APR determination
- FDIC, Savings Are Great for Short-Term Goals Too
Source links and illustrative calculations checked on 2026-09-22 (UTC). This article was prepared with AI-assisted research and drafting, followed by source and calculation checks. This is not an independent human or professional review. Read our editorial policy or report a correction.
