Compound Interest Rate Converter
Convert interest rates between different compounding periods, calculate APY/EAR, compare equivalent rates, and see how compounding affects long-term growth.
Convert Interest Rate
Conversion Result
What Is the Effective Annual Rate (EAR) or APY?
The Effective Annual Rate (EAR), often closely related to APY for deposit and savings products, shows the annual effect of compounding. It allows rates with different compounding frequencies to be compared on a common annual basis.
For example, a nominal annual rate compounded monthly does not produce exactly the same annual yield as the same nominal rate compounded annually. This calculator converts the nominal rate so the resulting effective annual yield remains equivalent.
Compound Growth Calculator
Growth Projection
Compound Growth Over Time
Year-by-Year Projection
| Year | Contributions | Interest | Ending Balance |
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Compounding Frequency Comparison
See the equivalent nominal rate and effective annual rate for the same economic return at different compounding frequencies.
| Compounding | Periods / Year | Equivalent Rate | Effective Annual Rate |
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Why Does Compounding Frequency Matter?
If the nominal rate stays unchanged, increasing the compounding frequency generally increases the effective annual yield. However, when this calculator converts an equivalent rate, it adjusts the nominal rate so the effective annual yield remains the same.
Compound Interest Rate Converter
The 5iTech Compound Interest Rate Converter helps you convert a nominal annual interest rate from one compounding frequency to another while preserving the same effective annual return. It can be used to compare annual, semi-annual, quarterly, monthly, weekly, daily and continuous compounding.
The calculator is useful when two financial products quote interest using different compounding conventions. Instead of comparing the headline rates alone, you can calculate the effective annual rate and equivalent nominal rate.
Nominal Interest Rate vs Effective Annual Rate
A nominal annual interest rate is a stated annual rate before the effect of intra-year compounding is considered. The effective annual rate accounts for how often interest is compounded during the year.
Example
Suppose a rate is quoted at 5% compounded monthly. The nominal rate is 5%, but the effective annual rate is slightly higher because interest is added multiple times during the year.
This distinction is important when comparing savings accounts, deposits, investments, loans and other products that use different compounding conventions.
Compound Interest Formula
For periodic compounding, the standard compound interest formula is:
Where:
- A = future value
- P = starting principal
- r = annual interest rate in decimal form
- n = number of compounding periods per year
- t = time in years
For continuous compounding, the corresponding formula is:
How to Convert Interest Rates Between Compounding Periods
First, the calculator determines the effective annual rate generated by the original nominal rate and compounding frequency. It then calculates the nominal rate at the new frequency that produces the same effective annual rate.
This means the converted rates are economically equivalent under the assumptions of the mathematical model. The displayed nominal percentages may be different, but their effective annual yield is approximately the same.
APR, APY and EAR: What’s the Difference?
- Nominal annual rate: A stated annual rate before intra-year compounding is reflected.
- APY: Annual Percentage Yield generally reflects the effect of compounding for deposit and savings products.
- EAR: Effective Annual Rate is the mathematically effective annual rate after compounding.
- APR: Annual Percentage Rate can have product-specific and regulatory meanings, particularly for credit and lending. Always check how a quoted APR is defined before comparing it directly with an APY.
What Can You Use This Calculator For?
- Convert annual interest to monthly equivalent rates.
- Convert monthly rates to annual equivalent rates.
- Compare quarterly and monthly compounding.
- Calculate effective annual yield.
- Compare different compounding frequencies.
- Estimate long-term compound growth.
- Include recurring contributions in a growth scenario.
- Understand the effect of compounding frequency.
- Check how an interest rate grows over multiple years.
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Frequently Asked Questions
What is a compound interest rate converter?
A compound interest rate converter changes a nominal annual rate from one compounding frequency to another while maintaining the same effective annual return.
What is APY?
APY, or Annual Percentage Yield, expresses the annual return after accounting for the effect of compounding. It is useful for comparing rates quoted with different compounding frequencies.
Is a 5% monthly compounded rate the same as 5% annually compounded?
No. If the nominal rate is exactly 5% in both cases, monthly compounding produces a different effective annual yield from annual compounding. The difference results from interest being added to the balance more frequently.
Does the converted rate have the same effective return?
Yes. The purpose of the conversion is to calculate the nominal rate at the new frequency that produces the same effective annual rate, subject to the assumptions of the formula.
Can I convert monthly interest to annual interest?
Yes. Select Monthly as the current compounding frequency and Annual as the target frequency.
Does this calculator support continuous compounding?
Yes. Continuous compounding uses the exponential form of compound interest and is available as both a source and target compounding frequency.
Does the calculator use a currency?
No. The calculator intentionally does not display currency symbols, making it suitable for users around the world. Enter values in whatever currency or unit applies to your situation.
Are the calculations sent to a server?
The calculator performs its calculations in your browser. No financial amount needs to be sent to a server for the calculation.
Calculation Methodology and Disclaimer
Results are mathematical estimates based on the values entered by the user. The calculator assumes a constant interest rate and the selected compounding convention.
Real financial products may have additional conditions such as fees, taxes, changing rates, minimum balances, withdrawal restrictions, day-count conventions or product-specific compounding rules.
This calculator is provided for educational and planning purposes and is not financial, investment, tax or legal advice. Verify the terms of an actual financial product with the relevant provider before making a financial decision.