The rate on your statement and the rate in the advertisement are two different figures with almost the same name. Advertised APY is a forecast. Annual percentage yield earned is a measurement of what the bank actually paid you.
How it works
Regulation DD defines the calculation: take the interest actually credited over a statement period, divide it by the average daily balance you held, then annualise the result over the number of days in the period. The average daily balance matters — the rule requires the balance for each day summed and divided by the number of days, not the closing figure.
Why your statement rate is lower than the advertised rate
Usually nothing is wrong. Advertised APY assumes a fixed sum sits untouched for a full year. Real accounts do not behave that way: money goes in and out, so the average daily balance differs from the balance you think of as yours, and a bank paying a variable rate may have changed it mid-period. If the two figures are far apart and your balance was steady, that is worth a call to the bank.
What this does not include
This annualises one period that has already happened. It is not a projection, and annualising a short period magnifies anything unusual about it — a 30-day period with an odd balance produces a headline rate that will not repeat.
How to use this calculator
- Enter the interest paid, exactly as printed on the statement.
- Enter the average daily balance for the period. Many statements print it; if not, it is the sum of each day’s balance divided by the number of days.
- Enter the number of days the statement covers.
Frequently asked questions
Why not just use the closing balance?
Because Regulation DD does not, and using it would give the wrong answer whenever your balance moved. If you deposited a large sum on the last day of the period, the closing balance is far above what actually earned interest, and the rate you calculate would look far too low.
Should APYE match the advertised APY?
Only if your balance was completely steady and the rate did not change. Otherwise a gap is normal and expected, not evidence of an error.
Can APYE be higher than the advertised APY?
Yes — a promotional rate, a bonus credited during the period, or a balance that fell after the interest was calculated can all push it above. Annualising a short period exaggerates the effect.
