Nominal interest rate calculator

Type a nominal rate and compounds per year. 5% and 12 give 5.12 %. 8% and 4 give 8.24 %. 5% and 1 give 5.00 %. The result is effective, with a dot and a space before %.

Not a bank offer. The calculator computes effective from nominal: (1 + (nom/100)/n)^n − 1. Growing a principal lives on compound interest.

Input data

Results

Enter data and click Calculate.

How it works

Nominal interest rate in this calculator goes into the formula, and the result shows effective. 5% and 12 compounds give 5.12 %. 8% and 4 give 8.24 %. 5% and 1 give 5.00 %. The code keeps two decimal places and appends a space and %.

Field a is the nominal rate in percent. Field b is compounds per year after floor. Empty or 0 falls to 1. At n = 1 effective equals nominal, hence 5.00 %.

5.12 % at 5% and 12 is (1 + 0.05/12)^12 − 1, times 100. The dot in 5.12 stays from two decimal places, even if you type 5,0 in the field. That is not the header currency format.

Compound interest next door already takes a rate and multiplies principal by years. There is no amount here. Only the swap from nominal to effective at a given n.

Type 5 and 12, then Calculate. A comma in 5.5 works in field a. A school sketch, not APR from a contract and not a central-bank table.

5% and 12 give 5.12 %. 8% and 4 give 8.24 %. 5% and 1 give 5.00 %. Another n at the same nominal gives another effective.

Formula

effective = (1 + (nom/100) / n)^n − 1, n = max(1, floor(b) or 1)

How to use

  1. Type the nominal rate, for example 5.
  2. Type compounds per year, for example 12.
  3. Click Calculate. The result shows 5.12 %.
  4. 8 and 4 give 8.24 %. 5 and 1 give 5.00 %.
  5. An amount times a rate lives on compound interest. Here only the rate swap.

5% and 12 give 5.12 %

Effective = (1 + (nom/100)/n)^n − 1. 5% with 12 compounds shows 5.12 %. This is not APR.

nominal
Field a, the rate you type. 5 at n = 12 gives 5.12 %. At n = 1 it stays 5.00 %.
effective
What the result prints. 8% and 4 give 8.24 %. The dot is from two decimal places.
compounds
Field b, n per year. Empty falls to 1. A larger n lifts effective at the same nominal.

Examples

Example 1

  • nominal 5%
  • n = 12

5.12 %

What effective from 5% with 12 compounds? 5.12 %. A dot from two decimal places.

Example 2

  • nominal 8%
  • n = 4

8.24 %

What from 8% with 4 compounds? 8.24 %. Quarterly.

Example 3

  • nominal 5%
  • n = 1

5.00 %

What from 5% with 1 compound? 5.00 %. Nominal equals effective.

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Common questions

What effective from 5% with 12 compounds?

5.12 %. (1 + 0.05/12)^12 − 1, then two decimal places and a space before %.

What from 8% with 4?

8.24 %. Four compounds a year.

What from 5% with 1?

5.00 %. At n = 1 effective matches nominal.

Is the result the nominal rate?

No. You type nominal. The result is effective from n.

Why is there a dot in 5.12 %?

That is how the script writes it: two decimal places + space + %. Not a currency format.

What if n is empty or 0?

the integer part of (b) or 1, then max with 1. It falls to one compound.

Is this APR from a contract?

No. A rate swap only. A bank and a tax office count another way.

Where do I multiply principal?

On compound interest or on interest with compounding. There is no amount here.

Does a comma in 5.5 work?

Yes in field a. The result still comes out with a dot, at other n too.

Knowledge sources

Effective from nominal uses the rate and compounding count you type. This is not a bank offer.

Page updated in 2026.