Nominal vs Effective Rate: Why the Headline Rate Is Not the Whole Story
Two loans can share the same headline rate and still cost different amounts. Compounding frequency is the hidden difference.
What is the APR Calculator?
A nominal rate that compounds monthly or daily earns interest on interest during the year, so the true yearly cost is higher than the headline rate. The effective annual rate formula raises the per-period rate to the number of periods in a year and subtracts one, giving the single yearly rate that matches the compounded result.
How to use it
- Enter the nominal annual rate as a percentage.
- Choose how often interest compounds.
- Press Calculate to see the effective annual rate.
Worked example
Nominal rate 12% compounding monthly: effective annual rate about 12.68%.
Why is my effective rate higher than the rate I was quoted?
Because interest compounds: each period's interest is added to the balance, and the next period charges interest on that larger balance. The more often this happens in a year, the more the effective yearly rate rises above the nominal rate. The calculator shows exactly how much higher it is for your compounding frequency.
Frequently asked questions
What is the difference between nominal and effective rates?
The nominal rate is the headline rate before compounding. The effective rate includes the effect of compounding, so it is the rate you actually experience over a full year.
Does more frequent compounding matter much?
At low rates the difference is small, but at high rates daily compounding can push the effective rate noticeably above the nominal rate.