Calcs4All

APR 23 · 2026

APY calculator

Convert a quoted nominal annual rate and compounding schedule into APY.

What this calculator covers

Use this APY calculator to translate a quoted nominal annual rate into the yield you actually earn after the stated compounding schedule is applied.

That matters because the same quoted rate can produce a different effective annual yield depending on whether interest compounds yearly, monthly, or daily.

The walkthrough keeps the periodic-rate step visible so it is easier to compare account quotes on a like-for-like basis.

Frequently asked questions

Why is APY higher than the quoted nominal rate?
Compounding adds interest on previously earned interest within the year. The more frequently interest compounds, the larger that gap between nominal rate and actual yield becomes.
How do I compare two savings accounts with different compounding schedules?
Convert both to APY using this calculator with each account's nominal rate and compounding frequency. APY puts both on a level playing field because it reflects the full one-year effect of compounding.
Does daily compounding make a significant difference over monthly?
At typical savings rates the gap is small — often a fraction of a basis point — but it becomes more meaningful at higher rates or over longer periods. The calculator shows the exact difference so you can judge the magnitude yourself.
Does APY account for fees or taxes?
No. APY is a pre-tax, pre-fee rate that reflects only the compounding math on the stated nominal rate. Fees, account minimums, and taxes reduce what you actually keep.

Tool

Run the calculation

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RESULT · APY

â„–070

Primary result

4.59%

A nominal rate of 4.50% compounded 12 times per year produces an APY of 4.59%.

Nominal annual rate
4.50%
Periodic rate
0.3750%
APY
4.5940%
$1 after one year
$1.045940

Step-by-step solution

  1. 1.Convert the quoted annual rate into a periodic rate: 4.50% ÷ 12 = 0.3750% per period.
  2. 2.Compound that periodic rate across 12 periods to find the effective one-year growth factor of 1.045940.
  3. 3.Subtract 1 from the one-year growth factor to read the effective annual yield, or APY, of 4.5940%.

Walkthrough

Visual walkthrough

APY turns a quoted nominal rate into the actual one-year yield after the stated compounding schedule does its work.

  1. 01

    Break the nominal rate into compounding periods

    4.50% ÷ 12

    The quoted annual rate only becomes usable after it is converted into the rate earned during each compounding interval.

  2. 02

    Compound through the full year

    (1 + r / n)^n = 1.045940

    Running the periodic rate through every compounding event shows how much one starting dollar becomes after one year.

  3. 03

    Read the effective annual yield

    The gap between the one-year balance and the original dollar is the APY, which captures the effect of compounding.

    4.59% APY