How To Use Our Blended Rate Calculator
Use the calculator above to estimate your blended mortgage rate across multiple active home loans, such as a first mortgage and a HELOC.
Keep in mind that this is a planning tool, not a loan estimate or refinance quote. It shows your combined balance-weighted interest rate based on the loan balances and rates you enter.
| Input |
What It Means |
Why It Matters |
| Loan balance |
The current principal balance of each mortgage, HELOC, or home equity loan |
Larger balances have more influence on the blended rate |
| Interest rate |
The current rate attached to each active loan |
This determines the annual interest cost assigned to each balance |
| Number of active loans |
The loans you want included in the calculation. If you don't want loans 3 and 4 included, leave the balance at $0. |
The calculator combines all nonzero balances into one weighted result |
How The Calculator Works
A blended mortgage rate is the single balance-weighted rate that reflects the annual interest cost of all your active home loans combined.
Borrowers often use it when they have a first mortgage and a HELOC and want one comparison number instead of evaluating each rate separately.
This calculator estimates your blended rate by multiplying each loan balance by its interest rate, adding those weighted interest amounts together, and dividing by the total balance across all active loans.
If any loan has a $0 balance, the model excludes it from the calculation.
How The Rate Calculation Works
The formula is straightforward: The calculator multiplies each loan balance by its interest rate, adds those amounts together, and then divides by your total loan balance.
That creates a fast planning estimate, not a full borrowing-cost analysis. It shows the single rate that would produce the same total annual interest charge as all included loans combined.
For example, if you have a $300,000 first mortgage at 6.5% and a $75,000 HELOC at 8.5%, the weighted annual interest is $19,500 plus $6,375, or $25,875 total. Divide that by the $375,000 combined balance and the blended rate is 6.90%.
When A Blended Rate May Be Useful
A blended rate can be useful when you are trying to compare the cost of keeping multiple home loans versus refinancing into one new loan.
That often comes up when you have a low fixed first mortgage and a higher-rate HELOC, or when you want to know whether combining both debts into a new mortgage could reduce your overall interest cost.
It can also help when you want a cleaner benchmark before comparing your current setup with a refinance offer.
What The Calculator Can And Cannot Tell You
The calculator is useful for estimating your combined interest rate across multiple loans.
It cannot tell you your total monthly payment, your refinance closing costs, your APR, or whether refinancing is the better choice overall. It also does not account for amortization differences, loan terms, or future HELOC rate changes if your line of credit has a variable rate.
The Bottom Line
Our blended rate calculator is best used as a comparison tool. It can help you estimate the combined interest cost of multiple home loans so you can better evaluate whether keeping both loans or refinancing into one makes more sense.
Frequently Asked Questions
What Is A Blended Interest Rate On A Mortgage?
A blended interest rate is a balance-weighted average across multiple active home loans. It is not the same as taking a simple average of the rates.
How Is A Blended Mortgage Rate Calculated?
The calculator multiplies each loan balance by its interest rate, adds those totals together, and divides by the total balance across all active loans.
Does The Calculator Include Fees Or Closing Costs?
No. The blended rate reflects interest cost only. It does not include lender fees, points, or closing costs.
Does The Blended Rate Show My Total Monthly Payment?
No. It only reflects the weighted interest rate across your loans. Monthly payment depends on each loan’s term, amortization, and repayment structure.
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