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Comparison Rate Formula Calculator

Calculate the true cost of a loan by including interest rates and fees.

Loan Amount ($)

Advertised Interest Rate (%)

Loan Term (Years)

Upfront Fees ($)

Monthly Ongoing Fees ($)

The Calculated Comparison Rate is: 0.00%

How to Calculate Comparison Rate Formula

The comparison rate is a statutory tool designed to help consumers identify the true cost of a loan. While an "advertised rate" only accounts for the interest charged on the principal, the comparison rate formula incorporates most upfront and ongoing fees, expressed as a single percentage.

The Core Comparison Rate Formula

There is no simple "one-line" algebraic formula for the comparison rate because it requires solving for the Internal Rate of Return (IRR). Essentially, you must find the interest rate $ r $ that makes the present value of all future repayments (including fees) equal to the loan amount minus upfront costs.

Loan Amount – Upfront Fees = Σ [ (Monthly Repayment + Ongoing Fees) / (1 + r)^n ]

Key Variables Explained

Loan Amount: The total principal you intend to borrow.
Advertised Rate: The nominal annual interest rate quoted by the lender.
Loan Term: The duration over which the loan is repaid (usually in years).
Upfront Fees: Application fees, legal fees, or valuation costs paid at the start.
Monthly Fees: Service or account-keeping fees charged every month.

Step-by-Step Calculation Example

Imagine you are looking at a loan with the following details:

Principal: $150,000
Interest Rate: 5.00% p.a.
Term: 25 Years
Upfront Fee: $600
Monthly Fee: $10

Step 1: Calculate the standard monthly repayment on the $150,000 at 5%. This equals approximately $876.89.

Step 2: Add the $10 monthly fee to the repayment, making it $886.89.

Step 3: Deduct the upfront fee from the loan principal ($150,000 – $600 = $149,400).

Step 4: Find the interest rate required to pay off $149,400 with a monthly payment of $886.89 over 25 years. This results in a Comparison Rate of 5.12%.

Why the Comparison Rate is Crucial

Without the comparison rate, a lender could advertise a very low interest rate of 4.5% but charge a $2,000 annual fee. This would actually be more expensive than a loan with a 4.8% rate and zero fees. The comparison rate formula "levels the playing field" so you can compare different loan products accurately.