APY Calculator (APR to APY)
Pick a direction, enter the rate you were quoted and how often it compounds. You'll get the converted rate, the gap in percentage points, and what that gap is worth on your balance.
Convert
The rate you were quoted
Savings accounts usually compound daily or monthly
To see what the difference is worth in dollars
APY (what you earn)
5.12%
from 5.00% APR, compounded monthly
Difference
0.12
percentage points between APY and APR
On your balance
—
Enter a balance to see dollars
APR and APY in one breath
APR is the rate before compounding; APY is the rate after it. If a bank pays 5% APR in twelve monthly installments, each month's interest joins the balance and earns its own interest for the rest of the year, and the year ends 5.12% higher, not 5.00%. That extra 0.12 is compounding's signature, and APY exists so you don't have to do the exponent yourself. The two numbers describe one account; the only question is whether interest-on-interest has been counted yet.
The flattering number, each way
Notice the pattern in how rates reach you: savings offers arrive in APY (the bigger number), loan offers lead with APR (the smaller one). U.S. disclosure rules actually require exactly that, which keeps comparisons within each category honest, but it means the headline number changes meaning when you cross from saving to borrowing. The place it stings is revolving debt: a 24% APR card compounds daily into roughly 27% effective, which is one reason balances grow faster than the sticker rate implies and why paying them down is the highest guaranteed return most people can get.
Real, but small, until the rate is big
Compounding frequency is the least important dial on this page. Daily versus monthly moves a 5% savings rate by a hundredth of a point; what moves real money is the rate itself and the years you leave it alone, which the compound interest calculator makes vivid. So spend your attention where the leverage is: getting cash into a high-yield account at all, and keeping an eye on the rate over time, since banks adjust them quietly. Watching what your accounts actually earn each month, across all of them, is the kind of ongoing bookkeeping Stoia was built to do for you.
Frequently asked questions
What is the difference between APR and APY?
APR is the plain annual rate before compounding; APY is what you actually earn or pay once interest starts earning interest on itself. A 5% APR compounded monthly works out to 5.12% APY. Same account, two ways of describing it.
Why do savings accounts quote APY but loans quote APR?
Partly regulation: U.S. rules require deposit accounts to advertise APY and loans to disclose APR. It also happens that each side's required number is the flattering one: APY is the bigger figure on savings, APR the smaller figure on debt. Knowing which one you're looking at is most of the battle.
How much does compounding frequency actually matter?
Less than people expect at savings rates: 5% APR is 5.12% APY compounded monthly and 5.13% compounded daily. It matters more at debt rates: a 24% APR credit card compounding daily is effectively about 27% a year. The gap grows with the rate.
Does APY include fees?
No. APY only accounts for compounding, so a monthly maintenance fee can quietly erase the interest a low balance earns. Loan APR is the opposite: it is designed to fold certain upfront costs in, which is why a loan's APR can be higher than its note rate.
Which number should I use to compare accounts?
Compare like with like: APY against APY for savings accounts and CDs, APR against APR for loans. Since every U.S. bank must quote savings in APY, that comparison is already apples to apples; this converter is for the times you're handed the other number.
Does this calculator save my numbers?
No. Everything runs in your browser and disappears when you leave. Nothing is uploaded or stored.
Want this to update itself?
Stoia connects your real accounts and keeps the full picture current: net worth, budgets, and goals. Launching in 2026.