Free · no signup

80/10/10 Piggyback Calculator — The Break-Even Against PMI

A piggyback is not a way of avoiding a cost — it is a second mortgage that replaces an insurance premium with interest. The premium has a legal end date and the second mortgage does not, so the honest answer is a break-even, not a winner. This runs both structures at the same down payment and tells you which month it flips.

Jump to calculator Read the guide

Educational calculators — always consult a licensed professional before making financial decisions.

Your purchase

01Price and cash down

Both structures buy the same house with the same cash, so these two set the total debt on each side.

What is the purchase price of the home?

Both structures buy the same house — this sets the size of every loan below.

How much are you putting down in cash?

The '10' in the middle of 80/10/10. Identical on both paths, so the comparison is fair.

1%30%

Cash down $40,000

02Second lien

The share of the price borrowed on the second loan. The first mortgage has to land at 80% of the price or below to avoid PMI.

The classic 80/10/10, paired with 10% cash.

First mortgage $320,000 (80.0% LTV) · second lien $40,000

03How long you keep the loans

Until you expect to sell or refinance. Costs on both paths are totalled up to this point, so the cheaper structure can change with it.

Tap to edit

130

04First mortgage

Seeded from the published survey average. The rate and term apply to both paths, so they move both costs together.

First-mortgage rate?

Freddie Mac's 30-year survey average was 6.67% for the week of August 13, 2026.

2%15%

First-mortgage term?

Applied to both paths.

The default, and what the worked examples use.

05Second-lien terms

Take these from the second lender's quote. The term moves the answer more than the rate does; closing costs land in month one.

Second-lien rate?

Bankrate's home equity loan average was 8.1% APR (published range 5.90%–10.25%) on August 12, 2026.

3%18%

Second-lien term?

This changes the answer more than the second-lien rate does.

The default here and in the guide's worked example.

Closing costs on the second lien?

Seeded at $0 on purpose — we do not have a citable national figure, so we do not invent one.

$0$20K

06PMI on the single loan

Mainly set by your credit score. It is charged only until the balance is scheduled to reach 80% of the price.

0.46%1.5%

The piggyback costs less over 10 yr

$12,827

Cost is interest + PMI + second-lien closing costs. $227,563 on the piggyback against $240,390 on the single insured loan.

Piggyback payment, month one$2,396/mo

One loan + PMI, month one$2,481/mo

Break-evennone in this term

When PMI stops — and when the second lien doesn't

On the single loan, PMI of $165 a month can be cancelled on request in month 97 (8 yr 1 mo), when the balance is scheduled to reach 80% of the purchase price, and must terminate automatically by month 111 at 78%. That is $16,005 of insurance in total, and then the payment falls to $2,316 — below the piggyback's $2,396. The second mortgage has no equivalent date: it runs its full term unless you pay it off or refinance it.

The two structures, side by side

	Piggyback	One loan + PMI
Cash down	$40,000	$40,000
First mortgage	$320,000 (80.0% LTV)	$360,000 (90.0% LTV)
Second lien	$40,000	—
First-mortgage P&I	$2,059/mo	$2,316/mo
Second-lien payment	$337/mo	—
PMI	none	$165/mo until month 97
Month-one payment	$2,396/mo	$2,481/mo
Cost over 10 yr	$227,563	$240,390

The two paths never cross inside the first mortgage's term at these inputs — the piggyback is cheaper in every month of it. Change the second-lien term first if you want to see how sensitive that is; it moves the answer further than the second-lien rate does.

An estimate from published August 2026 survey ranges, not a quote. Cost means interest plus PMI plus second-lien closing costs — that measure already accounts for the two paths paying principal down at different speeds, but it does not discount future dollars. Both first mortgages are priced at the same rate, which understates any pricing adjustment a 90% LTV loan can carry. Second-lien closing costs are seeded at $0 because no citable national figure exists; enter your lender's number.

Your Saved Scenarios

No saved scenarios yet

What you'll need

Purchase price and the cash you are putting down
The size of the second lien — 10% for an 80/10/10, 15% for an 80/15/5
How long you expect to keep the loans before selling or refinancing
Optional: quoted rates, the second lien's term, and its closing costs

What you'll get

Both month-one payments — Two loans against one loan plus its premium
PMI's legal end date — Cancellation at 80% and automatic termination at 78%
Cost over your horizon — Interest plus PMI plus second-lien fees, both paths
The break-even month — When the cheaper structure changes — or that it never does

Two worked examples, so you can check the arithmetic

Both are re-run through the same module the calculator above uses, so nothing on this page can drift away from the math. The background to the comparison — what a second lien actually is, how the tax treatment differs, and why refinancing is harder with one — is in the 80-10-10 piggyback vs PMI guide.

1. $400,000, 10% down, 10% second lien over 20 years

First mortgage $320,000 at 6.67% over 30 years; second lien $40,000 at 8.1% over 20 years; against a single $360,000 loan at the same 6.67% carrying PMI of 0.55%.

Month-one payments: $2,059 + $337 = $2,396, against $2,316 + $165 PMI = $2,481.
PMI can be cancelled on request in month 97 and must terminate by month 111 — 9 years 3 months — for $16,005 of insurance in total.
Over ten years: $227,563 on the piggyback against $240,390 on the insured loan — $12,827 in the piggyback's favour.
Break-even: none. At these inputs the piggyback is cheaper in every month of the 30-year term.

That last line is worth pausing on, because it is not what a monthly-payment table implies. From month 97 the insured loan sheds its premium and pays $2,316 against the piggyback's $2,396 — monthly, it is now the cheaper of the two. It still never catches up on total cost, because a 20-year second lien retires principal fast enough to more than pay for its higher rate. Monthly cheaper and cumulatively cheaper are different questions, and most comparisons only answer the first.

2. Edge case — the same house, a 30-year second lien at 10.25%

Three inputs moved to the unfavourable end of their published ranges: the second lien priced at the top of Bankrate's band and stretched over 30 years, and PMI at the bottom of its band (0.46%).

The piggyback still starts cheaper, but by only $37 a month rather than $85.
PMI cancels on the same schedule — the balance does not care what the premium is — so month 97 and month 111 again, for $13,386 of insurance.
Break-even: month 111. Past that point the single insured loan is the cheaper structure and stays cheaper.

The break-even lands in the same month PMI would have terminated automatically anyway, which is as clear a statement of the trade as the numbers can make. It also shows where the piggyback's advantage in the first example actually came from: not the rate spread, but the 20-year amortization. Change the second-lien term before you change anything else.

What this calculator deliberately does not model

Each of these would need a number nobody publishes. Naming them is more useful than estimating them, because an invented figure moves a break-even by months without ever announcing itself.

The loan-level price adjustment on a 90% LTV first mortgage

Both paths are priced at the same first-mortgage rate so the comparison isolates the structure. In practice a single loan at 90% LTV can carry a small pricing adjustment that an 80% LTV first mortgage does not, which would tilt the result slightly further towards the piggyback. No reliable published figure for that adjustment was found, so it is not estimated here — it is named instead.

A variable HELOC second lien

This calculator amortizes the second lien at a fixed rate. Per the CFPB a HELOC usually carries a variable rate, runs an interest-only draw period, and then steps up when repayment begins. None of that is a fixed schedule, so modelling it as one would be a picture of a loan you do not have. Bankrate's 7.30% HELOC average is shown on the page as context, not fed into the math.

The time value of the payment difference

Cost here is interest plus PMI plus second-lien fees, which nets out the fact that the two paths pay principal down at different speeds. It does not discount cash flows: a dollar paid in month one counts the same as a dollar paid in month two hundred. If you would invest the monthly difference rather than spend it, that is a separate calculation.

Refinancing, resubordination and early payoff

The break-even assumes both structures run untouched. In reality a second lien makes a later refinance harder — Fannie Mae's Selling Guide (B2-1.2-04) generally requires the second-lien holder to sign a resubordination agreement — and paying the second lien off early ends its cost where PMI's end date is fixed by law. Both effects are discussed in the guide and neither is priced here.

How it works

Set the price, the cash down and the size of the second lien

Both structures buy the same house with the same cash, so both start from an identical total debt. That is what makes the two costs comparable — and it is why the split, not the down payment, is the variable here.

All three loans are amortized in full

The 80% first mortgage and the second lien on one side; the single loan above 80% LTV on the other, with its insurance premium charged monthly until the balance is scheduled to reach 80% of the purchase price.

The break-even month is the answer

PMI must be cancelled by law; a second mortgage runs its term. The calculator finds the month at which that asymmetry overtakes the piggyback's head start — or tells you it never does at your inputs.

The inputs, their published ranges, and where they came from

Input	Published range (August 2026)	What it does to the answer
First-mortgage rate	6.67% (Freddie Mac 30-year survey, week of Aug 13 2026)	Applied to both paths, so it barely moves the comparison — it moves both sides together.
Second-lien rate	8.1% average, 5.90%–10.25% range (Bankrate home equity loan, Aug 12 2026)	Matters less than the second-lien term. A higher rate on a short second still beats a low rate on a long one.
Second-lien term	10–30 years, lender's choice	The largest single lever on this page. A 20-year second retires principal fast enough to outrun PMI; a 30-year second does not.
PMI premium	0.46%–1.5% of the loan a year (Bankrate; driven mainly by credit score)	Sets how much the insured path pays before its statutory end date. Seeded at 0.55%, which is also our PMI calculator's 700–719 figure at 85.01–90% loan-to-value on a loan over 20 years.
PMI cancellation	80% on request, 78% automatic (Homeowners Protection Act)	Not an input — a legal rule. It is the only reason the insured path can ever win.
Second-lien closing costs	No citable national figure	Seeded at $0 rather than estimated. Whatever you enter lands in month one and pulls the break-even towards you.

Rates: Freddie Mac Primary Mortgage Market Survey — 30-year fixed averaged 6.67% for the week of August 13, 2026 (read 2026-08-19); Bankrate, Current Home Equity Loan Rates — national average 8.10% APR, range 5.90%–10.25%, as of August 12, 2026. Bankrate's survey quotes a 5-YEAR fixed-rate loan; applying it to a longer amortization is a simplification stated on the page (read 2026-08-19); HELOC context 7.3% (read 2026-08-19). PMI premium: Bankrate, Piggyback Loans: What They Are and How They Work — PMI runs 0.46% to 1.5% of the loan amount per year, depending mainly on credit score. Seeded at 0.55% because that value is also the 700–719 credit-score figure at 85.01–90% loan-to-value on a loan over 20 years on /pmi-calculator/, so the two tools agree at that score (read 2026-08-19). Cancellation thresholds: Consumer Financial Protection Bureau — Homeowners Protection Act (PMI Cancellation Act) examination procedures: automatic termination at 78% of original value, borrower-requested cancellation at 80% (12 U.S.C. §4902(a) and (b)). Loans the CFPB classifies as high-risk instead terminate at 77% or the amortization midpoint, whichever is earlier — this calculator assumes a standard loan (read 2026-08-20). All figures reflect the August 2026 survey period and are editable on the calculator above.

By RealCost Editorial TeamReviewed by RealCost Editorial TeamLast updated September 7, 2026 with September 2026 data

An 80/10/10 splits the purchase into a first mortgage at 80% of value, a second at 10%, and 10% down — avoiding mortgage insurance by keeping the first loan at 80% LTV. Whether it beats one loan with PMI depends on the second loan's rate against the premium you avoid, and on how long you keep it.

What this calculator is actually comparing

Both paths buy the same house with the same cash down, so both start from the same total debt. What differs is how that debt is arranged and what it costs.

This tool runs two complete amortisations against a third and reports which structure costs less and from which month. That last part matters more than the headline: the answer often flips partway through the loan, because PMI is temporary and a second mortgage is not.

Its PMI input starts at 0.55% of the loan a year, and you can change it. Our PMI calculator no longer uses a single rate: it prices PMI from a published mortgage-insurer rate card by loan-to-value and credit score. At this tool's default 10% down on a loan over 20 years, that card charges 0.28% a year at 760+, 0.55% at 700–719 (the 0.55% starting value) and 0.94% at 620–639 — so enter the rate for your own score. Both tools drop the premium on the same convention — 80% of the ORIGINAL value, not of a re-appraised one.

Why the rate environment decides this

The piggyback wins when the extra interest on the second loan costs less than the mortgage insurance it avoids. That comparison moves with rates, and it moves against the piggyback when rates are high.

The Freddie Mac Primary Mortgage Market Survey put the 30-year fixed average at 6.71% for the week ending September 3, 2026, with the 15-year at 6.04%. A second mortgage prices above the first — it is subordinate, so it is riskier — and the gap is not published in any weekly survey. We have not put a number on it here, because there is no equivalent benchmark for second-lien pricing and inventing one would decide the comparison by assumption. Use an actual quote.

The structural point survives the missing number: PMI ends and the second mortgage does not. On a conventional loan the premium comes off automatically at 78% of original value, and can usually be requested at 80%. The second loan runs to term unless you refinance or pay it off. So a long hold favours the piggyback less than the first-year arithmetic suggests, and a short hold favours it more.

Three things the monthly comparison does not price

·The conforming limit. Splitting the debt can keep the first mortgage under the conforming ceiling — FHFA set the 2026 baseline one-unit limit at $832,750, with a high-cost-area ceiling of $1,249,125. On an expensive house that is sometimes the real reason to use a piggyback, and it does not show up as a monthly saving at all.
·Refinancing later is harder. A second lien has to agree to resubordinate before you can refinance the first. Lenders usually do, but it is a step, a fee, and occasionally a refusal.
·The tax treatment. IRS Publication 936 limits home mortgage interest to the first $750,000 of acquisition debt ($375,000 married filing separately). Note also that the same publication states the itemised deduction for mortgage insurance premiums has expired — so PMI carries no offsetting tax benefit, which is a point in the piggyback's favour that older comparisons get wrong.

That last item is worth dwelling on, because a great deal of writing on this topic predates the change and still credits PMI with deductibility. It has none. If a comparison you read anywhere treats mortgage insurance as partly tax-deductible, it is out of date and its conclusion is skewed toward the single loan.

Methodology

Both financing paths are amortised in full from the same purchase price, down payment and total debt, and compared month by month. The PMI premium starts at 0.55% (editable), the 700–719 credit-score rate at 85.01–90% LTV on a loan over 20 years on the published rate card this site's PMI calculator prices from, and cancellation follows the 80%-of-original-value convention. Second-lien rates are not assumed — enter a real quote. The conventional benchmark quoted is the Freddie Mac PMMS for the week ending September 3, 2026; conforming limits are FHFA's 2026 values; deduction limits are from IRS Publication 936.

Sources

Freddie Mac — Primary Mortgage Market Survey (week ending September 3, 2026) — accessed 2026-09-07
FHFA — Conforming Loan Limit Values for 2026 — accessed 2026-09-07
IRS — Publication 936, Home Mortgage Interest Deduction — accessed 2026-09-07

Related Calculators

PMI Calculator

The other half of this comparison on its own — your premium by credit-score band, and the month it can be cancelled.

Mortgage Calculator

The full payment on either first mortgage once taxes and insurance are added to the P&I above.

Closing Costs Calculator

A piggyback means two loan closings. This prices the first one; your lender's fee sheet prices the second.

HELOC Calculator

If the second lien is a line of credit rather than a fixed loan — variable rate, draw period, and the step-up after it.

About this calculator

What is an 80/10/10 piggyback loan?

Three numbers, in order: an 80% first mortgage, a 10% second mortgage behind it, and 10% of the price in your own cash. The point of the split is the first number — at exactly 80% loan-to-value a first mortgage does not require private mortgage insurance. On a $400,000 home that is $320,000 on the first mortgage, $40,000 on the second lien and $40,000 down. You are not avoiding the cost of a small down payment; you are financing the gap with a second loan instead of insuring it.

Is an 80/10/10 cheaper than paying PMI?

It depends on the second lien's term far more than on its rate, and on how long you keep the loans. At $400,000 with 10% down, a 6.67% first mortgage, a 8.1% second lien over 20 years and PMI at 0.55%, the piggyback costs $227,563 over ten years against $240,390 for the single insured loan — $12,827 cheaper, and it stays cheaper for the whole 30 years. Stretch the same second lien to 30 years at 10.25% and price PMI at 0.46% instead, and the two cross in month 111: past that point the insured loan is the cheaper one.

When does PMI actually stop?

By law, not by negotiation. Under the Homeowners Protection Act you may request cancellation once the balance is scheduled to reach 80% of the original value, and the servicer must terminate it automatically at 78%. On the $360,000 loan in the example that is month 97 and month 111 respectively — $16,005 of insurance in total, after which the payment drops to $2,316. A second mortgage has no such date. It ends when its term ends, or when you pay it off or refinance it.

Why is the piggyback's monthly payment lower but its total cost sometimes higher?

Because those are two different questions and the answers can point opposite ways. In the example the piggyback starts $85 a month cheaper, but from month 97 the insured loan sheds its premium and pays $2,316 against the piggyback's $2,396 — monthly, it is now the cheaper one. Whether it ever catches up on cumulative cost depends on the second lien's amortization: a 20-year second retires principal fast enough to stay ahead, a 30-year second does not. The calculator reports both figures rather than picking one.

Does an 80/15/5 work the same way?

Yes — the arithmetic is identical, and the calculator handles it. What matters is not the shape of the split but whether the first mortgage lands at or below 80% loan-to-value, because that is the line above which mortgage insurance is required. 5% cash with a 15% second lien reaches it; 5% cash with a 5% second lien does not, and in that case the first mortgage would still carry PMI, so the second lien buys you nothing but another loan. The calculator warns you when your inputs fall into that trap.

What does this calculator not include?

Four things, named rather than estimated. It prices both first mortgages at the same rate, which understates any loan-level pricing adjustment a 90% LTV loan can carry. It amortizes the second lien at a fixed rate, so it does not describe a variable-rate HELOC with an interest-only draw period. It does not discount future dollars — a payment in month one counts the same as one in month two hundred. And second-lien closing costs are seeded at zero, because no citable national figure was found for them; that seed is generous to the piggyback, and entering your lender's figure moves the break-even earlier.

Want to try different numbers?

Back to the calculator ↑