Finance category
Mortgage, loan, investing, tax, and money calculators.
Blended Mortgage Rate Calculator
The critical number when comparing a cash-out refinance against a HELOC on top of the current mortgage. This calculator produces the blended first + second rate so you can benchmark the refi offer fairly.
Blended rate
7.19%
Combined balance
$375,000
Combined monthly interest
$2,247
First mortgage share
86.67%
Second / HELOC share
13.33%
How the math works
Blended mortgage rate matters when evaluating piggyback loans, cash-out vs HELOC decisions, and consolidation refinances. A $325k first at 6.875% + $50k HELOC at 9.25% blends to about 7.19% — still below a typical cash-out refi that would require refinancing the entire balance.
When deciding between a cash-out refinance and a HELOC, the relevant comparison is not the new cash-out rate vs the old first-mortgage rate — it's the new cash-out rate vs the blended rate of (old first + HELOC).
How to Use
- Enter first mortgage balance and rate.
- Enter HELOC or second mortgage balance and rate.
- Read blended rate and the portion split.
Frequently Asked Questions
When should I compare blended rate to a cash-out offer?
Any time you're deciding between adding a HELOC/second vs doing a cash-out refi of the full balance. The refi rate needs to beat the blended rate, not just the current first rate, to make sense.
Does term matter in this comparison?
Yes. A cash-out refi resets to a new 30-year amortization, while the HELOC adds incremental debt without changing the first mortgage schedule. Shortening term on the refi is worth considering in the comparison.
What about tax treatment?
Mortgage interest on the first is deductible up to $750k if used for acquisition/improvement. HELOC interest is deductible only if used to improve the home. Shift the math on effective rate after-tax accordingly.
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