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Free Interest Rate Calculator - Convert and Calculate Rates

Calculate effective interest rates, convert between annual and monthly rates, and understand APR vs nominal rate differences.

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Calculate Interest Rate

Quick Answer

To convert annual rate to monthly, divide by 12 (simple) or use (1+annual)^(1/12)-1 for effective rate. APR includes fees in annualized cost. Effective rate accounts for compounding. Our calculator converts between all rate types.

Key Facts about Interest Rate Calculator:

  • Nominal rate: stated rate without compounding consideration
  • Effective rate: actual rate with compounding (always higher)
  • APR: annualized rate including fees
  • APY: annual yield with compounding (for savings)
  • Monthly rate = Annual rate / 12 (simple)
  • Effective monthly = (1+annual)^(1/12) - 1

Why Use Our Interest Rate Calculator?

Rate calculation tools:

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Rate Converter

Convert annual, monthly, daily rates.

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APR Calculator

Calculate APR including fees.

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Effective Rate

Find true rate with compounding.

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Multiple Formats

Work with various rate expressions.

Instant Results

Get calculations immediately.

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Private

Your data stays secure.

How to Interest Rate Calculator in 3 Easy Steps

Calculate rates:

1

Enter Rate

Input the known interest rate.

2

Select Type

Choose input and output rate types.

3

View Conversion

See converted rate instantly.

Why Use Our Calculator?

Understand true costs

Compare rates fairly

Convert any format

Make informed decisions

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Rate Clarity
Understand interest rates

Common Use Cases for Interest Rate Calculator

Perfect for:

Loan Comparison

Compare rates in same terms.

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Savings Analysis

Understand APY vs stated rate.

Convert Rates

Financial Planning

Calculate effective costs.

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Frequently Asked Questions

Everything you need to know about our interest rate calculator

What is the difference between APR and interest rate?

APR includes fees; interest rate is just the base rate. APR shows true cost.

Interest rate is the base cost of borrowing. APR includes fees and costs annualized. APR is always equal to or higher than the stated interest rate.

How do I convert annual to monthly rate?

Simple: divide by 12. Effective: (1+annual)^(1/12)-1 for compounding accuracy.

Simple: divide by 12. Effective: (1+annual)^(1/12)-1. For accurate loan calculations, use the effective monthly rate.

What is effective interest rate?

True rate including compounding - always higher than nominal rate.

The actual rate when compounding is considered. A 12% nominal rate compounded monthly has ~12.68% effective rate due to interest-on-interest.

Still have questions? Try the tool yourself!

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