Finance category

Mortgage, loan, investing, tax, and money calculators.

80/10/10 Mortgage Calculator

The 80/10/10 piggyback keeps the first mortgage at 80% LTV (PMI-free) with a 10% second and 10% down. This calculator prices the two monthly payments plus the blended rate for the overall structure.

Purchase price

First (80%) rate

Second (10%) rate

First loan term (yr)

Second loan term (yr)

Combined monthly

$3,055

10% down

$48,500

First loan (80%)

$388,000

Second loan (10%)

$48,500

First P&I

$2,549

Second P&I

$506

Blended rate

7.17%

How the math works

The 80/10/10 mortgage keeps the first at 80% LTV (no PMI) with a second mortgage covering 10% and the buyer contributing 10% down. Historically a popular structure for buyers who could afford 10% down but wanted to avoid PMI.

Second loans are often 10-15 year fully amortizing to make sure the second is paid off before the first. Some structures use interest-only HELOCs as the second, which reduces initial payment but doesn't amortize.

Editorial noteMaintained by EveryCalc - Reviewed June 2026

EveryCalc calculators are designed for fast, practical estimates with transparent inputs and no required account. We use plain formulas, visible assumptions, and related tools so visitors can check the result from more than one angle.

Results are informational only. For financial, tax, legal, medical, construction, or other high-impact decisions, verify the output against primary sources or a qualified professional.

Learn more about our review process on the EveryCalc methodology page.

How this calculator works

What this page estimates

This 80/10/10 Mortgage Calculator is built to give a quick, browser-based estimate for 80/10/10 mortgage. The 80/10/10 piggyback keeps the first mortgage at 80% LTV (PMI-free) with a 10% second and 10% down. This calculator prices the two monthly payments plus the blended rate for the overall structure. The inputs stay on the page during normal use, and the result should be treated as an estimate for planning, comparison, or education rather than professional advice.

Calculation approach

The calculator applies the standard relationship implied by the inputs, then formats the answer so it can be checked and reused. For finance tools, the most important step is using consistent units, rates, time periods, and assumptions before comparing the result with another calculator or outside quote.

Example workflow

For example, start with a realistic value you already know, change one input at a time, and watch how the answer moves. That makes it easier to tell whether the result is being driven by the main amount, the rate, the time period, or a unit conversion.

Practical checks

Use current, real-world numbers when the result affects money, health, tax, or legal decisions.
Run a low, base, and high case when the inputs are estimates.
Check the related calculators below when the next decision depends on a different assumption.

How to interpret the 80/10/10 mortgage result

Best use

Use the result as a planning number for comparing payments, rates, returns, tax reserves, or cash-flow choices before you request a quote or make a commitment.

Cross-check

Compare the answer with the contract, lender estimate, tax form, brokerage statement, payroll record, or invoice that will control the real-world outcome.

Watch for

Do not rely on a single optimistic rate, return, or fee assumption. Money pages work best when you run low, base, and high cases and keep professional advice separate from the estimate.

This page belongs to the Finance calculator library, so the answer should be read in the context of the decision you are modeling rather than as a universal rule.

Before relying on this 80/10/10 mortgage estimate

Most calculator mistakes come from the inputs, not the arithmetic. Use this short audit before you reuse the answer in a spreadsheet, quote, application, or important conversation.

Confirm source numbers

Match balances, rates, fees, taxes, income, and payment dates against the lender quote, payroll record, tax form, statement, invoice, or contract.

Separate cash flow from total cost

A lower monthly payment can still cost more over time if fees, interest, taxes, or a longer term are hidden in the structure.

Run conservative cases

Test at least one higher-cost or lower-return case before using the output for a purchase, refinance, investment, loan, or tax decision.

Rerun this page when the rate, price, term, fee, tax rule, income, expense, or expected holding period changes.

How to Use

Enter purchase price.
Enter first and second loan rates.
Enter first loan term (usually 30 years).
Enter second loan term (often 15 years fully amortizing).

Frequently Asked Questions

When does 80/10/10 make sense?

Buyers with 10% down who want to avoid PMI. Especially valuable when PMI rates are high or the buyer expects to pay down the second mortgage quickly. Today, it often wins when second mortgages price below about 2% above first rates.

Can I refinance the second later?

Yes. Once you reach 80% LTV on the first alone (through appreciation or principal paydown), you can refinance to a single loan. Or combine both into one refinanced first mortgage.

Are 80/10/10s tax-efficient?

Often yes. The first is fully deductible (acquisition debt under $750k). The second is only deductible if used for acquisition/improvement (which it is in a purchase). Compare to PMI deductibility rules for your income.