Mortgage Calculators

Blended Rate Mortgage Calculator

This calculator helps you determine the effective, or blended, interest rate you would pay if you use a first and a second mortgage to finance the purchase of a home.

Inputs

First mortgage balance

First mortgage rate

Second loan / HELOC balance

Second loan rate

Years remaining

Estimates only. Adjust any value to recalculate instantly.

Results

Blended interest rate 6.395% on $285,000 of combined mortgage debt

Combined balance $285,000

Blended rate 6.395%

Monthly interest $1,518.75

Rate spread 6.00% / 8.50%

Debt by balance

First (6.0%) $240k
Second (8.5%) $45k

Combined balance Balance

Your blended rate of 6.395% is the weighted average across both loans. It is the figure to compare against a single cash-out refinance — refinancing only makes sense if the new rate beats this blend.

Combined amortization at the blended rateView table

Year	Principal	Interest	Balance
1	$4,781	$18,086	$280,219
2	$5,096	$17,772	$275,123
3	$5,432	$17,436	$269,691
4	$5,789	$17,078	$263,902
5	$6,171	$16,697	$257,731
6	$6,577	$16,291	$251,154
7	$7,010	$15,858	$244,144
8	$7,472	$15,396	$236,673
9	$7,964	$14,904	$228,709
10	$8,488	$14,379	$220,221
11	$9,047	$13,820	$211,173
12	$9,643	$13,225	$201,530
13	$10,278	$12,590	$191,252
14	$10,955	$11,913	$180,297
15	$11,676	$11,191	$168,621
16	$12,445	$10,422	$156,175
17	$13,265	$9,603	$142,911
18	$14,139	$8,729	$128,772
19	$15,070	$7,798	$113,702
20	$16,062	$6,806	$97,640
21	$17,120	$5,748	$80,521
22	$18,247	$4,620	$62,273
23	$19,449	$3,419	$42,825
24	$20,730	$2,138	$22,095
25	$22,095	$773	$0

How the blended rate mortgage calculator works

It weights each loan’s rate by its balance to produce a single blended rate across your first mortgage and any second loan or HELOC — the true average cost of your combined mortgage debt.

Worked example

Worked example: with first mortgage balance of $240,000, first mortgage rate of 6.00% and second loan / heloc balance of $45,000, the blended rate mortgage calculator shows blended interest rate of 6.395%.

Combined balance: $285,000
Blended rate: 6.395%
Monthly interest: $1,518.75
Rate spread: 6.00% / 8.50%

The formula

Blended rate = (balance₁ × rate₁ + balance₂ × rate₂) ÷ (balance₁ + balance₂).

Results are estimates for educational purposes and are not financial advice. Confirm exact figures with your lender, plan administrator or advisor.

Frequently asked

Questions about the blended rate mortgage calculator

What is a blended mortgage rate?

The balance-weighted average rate across all your home loans. It tells you the real overall cost when you carry both a first mortgage and a second loan or HELOC.

Why does the blended rate matter?

It is the rate to beat when considering a cash-out refinance. Refinancing both loans into one only makes sense if the new rate is below this blend.

Is a blended rate the same as APR?

No — APR includes fees on a single loan, while a blended rate simply averages the interest rates across multiple loans by balance.

Is the Blended Rate Mortgage Calculator free to use?

Yes. Every calculator on FinCalculators is completely free, with no sign-up, login or paywall. You can run as many scenarios as you like.

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