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Piggyback Loan Calculator

A piggyback mortgage keeps the first loan at 80% LTV (PMI-free) with a second mortgage covering the gap. This calculator compares combined piggyback payments to a single loan with PMI to see which structure saves more.

Purchase price

First mortgage LTV %

conventional 80% no PMI

Second mortgage LTV %

First mortgage rate

Second mortgage rate

Alt PMI rate % / year

if single 90% LTV loan

Piggyback total monthly

$2,957

Single loan + PMI

$3,122

Piggyback monthly savings

$165

First loan payment

$2,549

Second loan payment

$408

Down payment

$48,500

How the math works

Piggyback loans split financing into two mortgages to keep the first at 80% LTV (PMI-free). Common structures: 80/10/10 (80% first + 10% second + 10% down) and 80/15/5 (for 5% down buyers). Compare against a single loan with PMI to see which wins monthly.

Piggyback second loans are typically HELOCs or closed-end seconds at higher rates than the first. Tax treatment: first mortgage interest deductible up to $750k; second interest only if used for acquisition/improvement. PMI is deductible for certain income levels. Model after-tax for apples-to-apples.

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 Piggyback Loan Calculator is built to give a quick, browser-based estimate for piggyback loan. A piggyback mortgage keeps the first loan at 80% LTV (PMI-free) with a second mortgage covering the gap. This calculator compares combined piggyback payments to a single loan with PMI to see which structure saves more. 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 piggyback loan 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 piggyback loan 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.
Set first mortgage LTV (usually 80%).
Set second mortgage LTV (10% for 80/10/10, 15% for 80/15/5).
Enter first and second rates.
Enter alternative PMI rate for the single-loan comparison.

Frequently Asked Questions

Why use a piggyback?

To avoid PMI. A single 90% LTV loan charges PMI until the balance hits 78%, often taking 5-10 years. A piggyback keeps the first at 80% permanently, saving PMI throughout the loan.

When does PMI beat piggyback?

When the second mortgage rate is meaningfully higher than PMI. At today's rates, PMI of 0.3-0.5% often beats piggyback seconds at 9%+. Run the numbers for your specific rate situation.

Are piggybacks available everywhere?

Most markets but not all. Some lenders offer combined first+second at the same closing. HELOC as the second is more widely available. Jumbo piggybacks are common for loans above conforming limits.