Calculator
What the APY Calculator does
APY Calculator: calculates APY % and APY − Nominal from Nominal Rate % p.a. and Compounds / Year. Formula: A = P x (1 + r/n)^(n x t). Example: nominal rate % p.a. 6 and compounds / year 12 gives APY % 6.17%.
Give the APY Calculator your Nominal Rate % p.a. and Compounds / Year and it works out APY % and APY − Nominal. Values update as you type, so comparing options is a matter of editing one field.
Typical users are anyone weighing up a loan. Small differences in rate or term compound into large differences in what you actually pay.
There is no back end here. The calculation runs where you are sitting, not on a server somewhere.
The field table, the method and a worked example are documented after the tool for anyone who wants to check the working.
What do the APY Calculator fields mean?
The APY Calculator uses 2 inputs. Nothing is blank on load, so you can see the shape of the answer before supplying your own figures.
| Field | What to enter | Default |
|---|---|---|
| Nominal Rate % p.a. | accepts 0.1 to 50 | 6 |
| Compounds / Year | accepts 1 to 365 | 12 |
How does the APY Calculator work?
n is how many times interest is compounded per year, so a higher n produces a larger maturity value for the same nominal rate.
Bad input produces an error, never a confident-looking wrong answer.
Worked example
These are the values the APY Calculator loads by default, and the result it produces from them. These are the exact values loaded when the page opens, and the answer they produce.
| Nominal Rate % p.a. | 6 |
|---|---|
| Compounds / Year | 12 |
| APY % | 6.17% |
|---|---|
| APY − Nominal | 0.17% |
How to use it
- Set Nominal Rate % p.a. (0.1 to 50).
- Put Compounds / Year (1 to 365).
- Skip the submit button; there is not one. Editing is enough.
- Check APY % and APY − Nominal on the right.
- Print gives a tidy version without the navigation, which is handy for attaching to a file.
What this tool does not do
- Fees, taxes and eligibility rules vary by product and are not included unless there is a field for them.
- Lender rounding rules differ, so the final figure on your statement may differ by a small amount.
- Edge cases at the very limits of the accepted range are handled, but rarely worth relying on.
- The tool trusts your numbers completely, so a mis-keyed digit propagates straight through.
Frequently asked questions
You need Nominal Rate % p.a. and Compounds / Year. Nothing starts empty, so the form is usable immediately, without filling anything in first.
Nominal Rate % p.a. accepts 0.1 to 50. Go outside it and you get an error against that specific field instead of a misleading number.
With the values loaded when the page opens, APY % comes out as 6.17%. Overwrite any of the starting values and the result follows.
No. Your browser is doing the computing, so we could not see the values even if we wanted to.
No payment and no login. Advertising covers the running costs.
It is precise to the method and honest about its scope: no calculator can know your eligibility, and eligibility is what usually moves the final number.