Finance · Loans & Credit

Blended Interest Rate Calculator

Combine multiple balances and annual rates into one balance-weighted average rate.

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Quick guide

How to use this calculator

  1. Enter the balances, rates, fees, and timing requested by the visible labels.
  2. Keep monetary entries in one consistent currency.
  3. Review the result together with the declared calculation convention and exclusions.

Calculation method

Calculation method

Blended rate = Σ(balance × annual rate) ÷ Σ(balance).

Entered fixed decimals are aggregated exactly. Iterative rate solving is bounded to a single nonnegative monthly cash-flow root and fails explicitly if the result is absent, too large, or not reliably representable.

Worked example

Worked example

A 1,000 balance at 10% and a 3,000 balance at 6% have a blended annual rate of 7%.

Blended rate = Σ(balance × annual rate) ÷ Σ(balance).

Supported inputs

Precision and limits

Visible input limits

Amounts are capped at 1e12, rates at 1000%, monthly periods at 1,200, and fixed decimals at 12 places. List tools accept 1–20 uniquely named rows.

Estimate, not a disclosure

Results model only the entered convention. They do not reproduce a lender statement, credit score, underwriting outcome, or jurisdiction-specific consumer-credit disclosure.

International scope

No currency, country, credit bureau, scoring model, statutory APR rule, fee classification, grace period, or issuer policy is assumed.

Calculator-specific assumptions

The result is a simple balance-weighted snapshot. It does not model different compounding, payment schedules, variable-rate changes, fees, or tax treatment.