Blended Rate Calculator
Combine two loans into one weighted blended rate so you can compare keeping both against refinancing into a single mortgage.
By Onias Derilus, Mortgage Capital · NMLS# 1859012 · Last Updated: June 2026
Balance Mix
The blended rate is the single average rate across both loans, weighted by balance. Use it to compare keeping two loans against refinancing into one. Estimate only.
A blended rate is the single average interest rate across two loans, weighted by how much you owe on each. It tells you the true effective rate on your combined debt.
It matters most when you are deciding whether to refinance. If a new single-loan rate is higher than your blended rate, consolidating could cost you more even if the new rate looks lower than your second loan.
These figures are estimates. For neutral, official guidance on mortgage costs and what lenders can charge, see the CFPB's Owning a Home guide.
How to Use This Calculator
- 1
Enter the balance and rate of your first mortgage.
- 2
Enter the balance and rate of your second loan or HELOC.
- 3
Read the blended rate across both balances.
- 4
Compare that blended rate to any single refinance offer before consolidating.
The Formula & Assumptions
Blended rate =
(B1 × R1 + B2 × R2)
÷ (B1 + B2)
B = balance, R = rate
Each loan rate is weighted by its share of the total balance, so a large low-rate first mortgage pulls the blended rate down even if a small second loan has a high rate.
The combined monthly interest is the sum of each balance times its rate, divided by twelve. It shows the interest portion only, not full principal-and-interest payments.
If you are weighing a cash-out refinance that replaces both loans, compare the new rate to this blended rate, not just to your highest-rate loan.
Frequently Asked Questions
Why does a blended rate matter for refinancing?
If you have a low first mortgage and a higher second loan, your blended rate may already be lower than a new single-loan rate. Refinancing both into one loan could raise your effective rate, so the blended rate is the number to beat.
Should I keep my second mortgage separate?
Often yes, when your first mortgage carries a much lower rate than current market. Replacing both with one new loan throws away that cheap first-loan rate. Compare the blended rate to any consolidation offer first.
Does the blended rate include my payment?
No. The blended rate is just the weighted average interest rate. Your actual payments depend on each loan term and amortization, which you can check with the mortgage payment calculator.
Can I blend more than two loans?
The math extends to any number of loans by weighting each balance by its rate and dividing by the total. This tool covers the two most common, a first mortgage plus a second loan or HELOC.
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Rates are illustrative only. APR and payments vary by credit score, loan amount, and market conditions. Subject to credit approval. Not a commitment to lend. NMLS# 1859012. Equal Housing Lender.
It calculates the single effective rate across two or more loans, weighted by each balance. It answers whether consolidating into one mortgage actually lowers your cost.
Blended Rate Calculator in Florida
Many Florida owners hold a low first mortgage from an earlier rate cycle alongside a newer home-equity line taken for a roof, impact windows, or an assessment. Blending those into one new mortgage usually raises the rate on the larger balance, so run the number before refinancing the whole stack.
How the Blended Rate Calculator Works
The calculator multiplies each balance by its rate, adds the results, and divides by the total balance. That weighted average is your true blended cost of borrowing.
The Blended Rate Formula, Explained
Blended rate = ((balance1 × rate1) + (balance2 × rate2)) / (balance1 + balance2)
Weighting by balance is the whole point. A small second mortgage at a high rate moves the blend far less than its headline rate suggests.
The blended rate ignores term. A consolidation that lowers your rate but stretches a nearly paid-off second lien back out to thirty years can still cost more in total interest.
The Complete Blended Rate Calculator Guide
The blended rate exists to stop a tempting mistake. A 9% home-equity line looks urgent next to a 4% first mortgage, and consolidating both feels like progress.
Weight the two by balance and the picture often reverses. Refinancing a large low-rate first just to clear a small high-rate second can raise your overall cost considerably.
Use the calculator before you apply. If the blended rate is already below the consolidation rate on offer, keeping the loans separate and attacking the small one directly is usually the cheaper path.
Blended Rate Calculator FAQ
Should I always consolidate to a lower rate?
Not necessarily. Compare the offered rate against your blended rate, not against the highest rate you hold. Term matters too, since stretching a short balance back out adds interest.
Does this include closing costs?
No. The blended rate compares borrowing costs only. Add the refinance closing costs separately before deciding, because they can outweigh a small rate improvement.