Rate Conversion (APR and EAR)
Translate between a nominal annual rate (APR) and the effective annual rate (EAR) it actually produces once compounding is applied. A 12% APR compounded monthly is a 12.68% EAR.
EAR from APR (Annual Compounding)
When compounding is annual, the effective annual rate equals the stated APR.
When to use: Use as a baseline — with annual compounding, nominal and effective rates are the same.
Formula
Variables
| Symbol | Name | Description | Unit |
|---|---|---|---|
| EAR | Effective Annual Rate | True annual return | % |
| k | APR | Stated annual percentage rate | % |
Real-Life Examples
Example 1: Annual Compounding
A savings account states 5% APR with annual compounding. What is the EAR?
Given
Step-by-Step
For these inputs, Effective Annual Rate is 5.000000% under the stated payment, compounding and accounting assumptions.
Example 2: Annual Bond Yield
A bond yields 8% with annual compounding.
Given
Step-by-Step
For these inputs, Effective Annual Rate is 8.000000% under the stated payment, compounding and accounting assumptions.
Frequently Asked Questions
This formula serves as a baseline reference. Use it to confirm that with annual compounding, no adjustment is needed. For other compounding frequencies, use the m-times or continuous EAR formulas to find the true annual rate.
These equations convert nominal interest rates and effective annual rates for the specified compounding convention. Regulatory APR may also reflect fees, cash-flow timing and product-specific rules; this conversion alone does not calculate every disclosed loan APR.