Finance · Savings & Banking

Interest Rate Converter

Convert an entered periodic rate to nominal and effective annual rates.

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Quick guide

How to use this calculator

  1. Enter the balance, rate, timing, fee, or contribution assumptions named by the fields.
  2. Use one currency and follow the stated nominal, effective, simple-interest, or compounding convention.
  3. Review the calculator-specific assumptions before comparing accounts or making a savings decision.

Calculation method

Calculation method

Nominal annual rate = periodic rate × periods per year. Effective annual rate = (1 + periodic rate)^periods − 1.

Entered fixed decimals are parsed exactly. Compound projections use stable exponential forms and preserve zero-rate cases exactly; money rounds only for display and a supported nonzero amount is not replaced by a misleading zero.

Worked example

Worked example

A 1% monthly rate converts to 12% nominal and approximately 12.6825% effective annually.

Nominal annual rate = periodic rate × periods per year. Effective annual rate = (1 + periodic rate)^periods − 1.

Supported inputs

Precision and limits

Visible input limits

Amounts accept up to 30 digits and 12 decimal places and are capped at 1e12 per input. Rates are capped at 1000%. Most projections are capped at 1,200 months or 100 years; narrower whole-number limits appear in field labels.

International scope

No currency, institution, current market rate, deposit-insurance rule, tax system, regulatory disclosure, or jurisdiction-specific product term is assumed.

Decision boundary

Results are arithmetic scenarios from visitor-entered assumptions, not account quotations, forecasts, tax advice, legal determinations, deposit guarantees, or recommendations.

Calculator-specific assumptions

The conversion assumes equal periods and compounding at the end of every period. Fees and irregular cash flows are excluded.