Blended Rate Calculator

Calculate your true blended interest rate across multiple loans, mortgages, or credit lines. Instantly determine your volume-weighted average cost of debt.

Primary loan balance USD Please enter a valid balance

Primary interest rate % Please enter a valid rate

Second loan balance USD e.g., HELOC or personal loan Please enter a valid balance

Second interest rate % Please enter a valid rate

Third loan balance (Optional) USD Please enter a valid balance

Third interest rate (Optional) % Please enter a valid rate

Calculation Results

Blended Interest Rate

— %

This is the true weighted average cost of your debt.

How to use this blended rate calculator

Enter your primary loan details

Input the remaining balance and current interest rate of your largest debt, such as your primary mortgage.

Add your secondary loans

Enter the balance and rate for any additional loans, such as a Home Equity Line of Credit (HELOC), car loan, or personal loan.

Get your instant blended rate

The calculator automatically weights each interest rate by its loan balance to reveal the true overall cost of your combined debt.

Blended Interest Rate Matrix (Primary Mortgage + Second Loan)

Primary Mortgage	Second Loan	Total Debt	Effective Blended Rate
$2,00,000 @ 3.5%	$25,000 @ 8%	$2,25,000	4.00%
$2,00,000 @ 3.5%	$50,000 @ 9.5%	$2,50,000	4.70%
$2,00,000 @ 3.5%	$1,00,000 @ 11%	$3,00,000	6.00%
$2,00,000 @ 3.5%	$1,50,000 @ 12%	$3,50,000	7.14%
$3,50,000 @ 4%	$25,000 @ 8%	$3,75,000	4.27%
$3,50,000 @ 4%	$50,000 @ 9.5%	$4,00,000	4.69%
$3,50,000 @ 4%	$1,00,000 @ 11%	$4,50,000	5.56%
$3,50,000 @ 4%	$1,50,000 @ 12%	$5,00,000	6.40%
$5,00,000 @ 5%	$25,000 @ 8%	$5,25,000	5.14%
$5,00,000 @ 5%	$50,000 @ 9.5%	$5,50,000	5.41%
$5,00,000 @ 5%	$1,00,000 @ 11%	$6,00,000	6.00%
$5,00,000 @ 5%	$1,50,000 @ 12%	$6,50,000	6.62%

Frequently asked questions

What is a blended interest rate?

A blended interest rate is the combined, weighted average interest rate across multiple loans. It accurately reflects your total cost of borrowing by accounting for the size of each loan, rather than simply averaging the interest rates together.

Why shouldn't I just average the two interest rates?

A simple average assumes both loans are exactly the same size. If you have a $400,000 mortgage at 3% and a $20,000 credit card at 20%, a simple average suggests your rate is 11.5%. However, because the low-rate mortgage makes up the vast majority of your debt, your true blended rate is much lower (around 3.8%).

Is a blended rate useful for mortgage refinancing?

Yes, it is essential. If you are considering taking out a HELOC or a second mortgage versus doing a cash-out refinance on your primary mortgage, you must compare the proposed cash-out refinance rate against the blended rate of your current mortgage plus the new HELOC. If the blended rate is lower than the cash-out refinance rate, the HELOC is usually the better financial choice.

Can I use this for hourly billing rates?

Yes. The mathematical formula is identical. Simply enter the number of hours worked into the "balance" fields, and the hourly rate ($/hr) into the "rate" fields. The tool will output your blended hourly billing rate across the project.

About this calculator

This blended rate calculator is a financial tool used by homeowners, real estate investors, and finance professionals to determine the true weighted cost of capital across multiple debts. It is most commonly used when deciding between a cash-out refinance and a Home Equity Line of Credit (HELOC).

The calculation uses the standard volume-weighted average formula:

Total Interest Impact = (Balance 1 × Rate 1) + (Balance 2 × Rate 2) + ...
Total Debt = Balance 1 + Balance 2 + ...

Blended Rate = Total Interest Impact ÷ Total Debt

By weighting the rates against their respective balances, you ensure that massive loans (like a primary mortgage) exert significantly more influence on the final percentage than smaller, high-interest debts (like an auto loan or credit card).