80/10/10 Piggyback Mortgage Calculator
Use this calculator to compare a classic 80/10/10 piggyback setup against one larger loan with PMI. It shows your first-lien LTV, combined LTV, monthly payment difference, and a practical 5-year cost comparison.
What you’ll get on this page
80/10/10 calculator + PMI comparison
Default settings use the classic 80/10/10 split: 80% first mortgage, 10% second mortgage, 10% down. You can test nearby combo structures too. This is a planning tool, not a lender quote.
How an 80/10/10 piggyback works in plain English
An 80/10/10 piggyback uses two loans at the same time when you buy the house. The first mortgage covers 80% of the purchase price. A second mortgage or HELOC covers another 10%. You bring the final 10% as your down payment.
The appeal is simple: on many conventional loans, PMI usually shows up when the first mortgage is above 80% loan-to-value. A piggyback structure keeps the first mortgage at 80%, which is why buyers use it as an alternative to PMI.
But there is no magic here. You are not “making” a cost disappear. You are replacing PMI with a second loan payment. Sometimes that wins. Sometimes it does not.
When this strategy can make sense
You want to avoid PMI, but still have meaningful cash down
If you can comfortably put 10% down and the second-lien pricing is reasonable, a piggyback can be cleaner than carrying PMI for years.
Your second-lien quote is competitive
The whole strategy depends on the actual quote. If the second mortgage rate is high, adjustable, or fee-heavy, the “PMI savings” can vanish quickly.
You want to keep the first mortgage at 80% LTV
That can matter for PMI planning and, in some cases, for pricing. But availability still depends on lender programs and underwriting.
You understand both loans
This is a strategy for buyers who are organized enough to handle two loan documents, two payment structures, and the risk of a second lien.
When it backfires
The second mortgage rate is much higher
A second lien often costs more than the first mortgage. If that second payment is expensive enough, the piggyback route can cost more than a single loan plus PMI.
The second lien is a HELOC with variable-rate risk
A HELOC can change as rates change. If you pick that structure just to avoid PMI, make sure you are not quietly adding a different kind of payment risk.
You focus only on PMI, not the total deal
CFPB explicitly warns that piggyback seconds may be marketed as cheaper, but that does not necessarily make them cheaper overall.
Your budget is already tight
If you are already stretching on the house, adding a second-lien payment can make the whole setup more fragile. In that case, the smarter move may be a cheaper home, a larger down payment later, or a different loan path.
What the calculator is actually comparing
Option A: Piggyback
First mortgage payment + second mortgage payment + monthly property costs.
Option B: Single loan + PMI
One mortgage payment + PMI estimate + the same monthly property costs.
It also estimates a 5-year carrying cost so you can stop judging the decision only by this month’s payment. The 5-year figure adds up interest on the loan(s) and PMI on the single-loan option, because that is where a lot of the hidden difference lives.
Vetted sources behind this page
- CFPB — What is a “piggyback” second mortgage?
- CFPB — What is mortgage insurance and how does it work?
- CFPB — What is a second mortgage or junior lien?
- Fannie Mae — LTV, CLTV, HCLTV, and subordinate financing
- Fannie Mae — Combined Loan-to-Value (CLTV) ratios
- Fannie Mae — Subordinate financing
Important note: lender program availability, pricing, fees, and underwriting vary. Use this page to plan smarter questions, not to assume every lender will offer the same combo structure.
Best tools + best videos
Best next tools on Up From Zero
Watch inside the post
Mortgage Explainer: The 80-10-10 Loan — useful for understanding the structure before you compare payment math.
What is PMI or Mortgage Insurance? — helpful because the whole piggyback decision is really a cost comparison against PMI.
FAQ
Does an 80/10/10 loan always beat PMI?
No. It can avoid PMI, but the second mortgage can still make the total deal more expensive. Compare the real monthly payment, the rate on the second, fees, and the first few years of cost.
Is a piggyback second mortgage the same as a normal second mortgage?
It is a type of second mortgage, but the key difference is timing. A piggyback second is created at the same time as the first mortgage to help finance the purchase.
Can I use a HELOC instead of a fixed second mortgage?
Sometimes. CFPB notes that a piggyback second can be a home equity loan or a HELOC. The big caution is that a HELOC may carry a variable rate, which adds payment uncertainty.
Do both loans count when I apply?
Yes. This is not a secret workaround. The second loan is still debt, and lenders consider simultaneous loan payments when evaluating affordability.
What is the main downside of 80/10/10?
The second lien can be expensive, and the structure is more complex than one loan. The “no PMI” headline can distract people from the actual total cost.
Next steps + internal links
If you are working through the mortgage cluster in order, this is the smartest sequence from here:
- How Much House Can I Afford in 2026?
- Mortgage Affordability Calculator
- Cash to Close Calculator
- Down Payment Calculator
- PMI Calculator
- How to Remove PMI From Your Mortgage
- Loan-to-Value (LTV) Calculator
- Combined Loan-to-Value (CLTV) Calculator
Planned next internal pages for this branch:
Disclosure
How to Use This Calculator
Enter the first mortgage amount, second mortgage (HELOC or piggyback loan) amount, and home value. The calculator shows your combined LTV and whether you qualify to drop PMI on the first mortgage by using the piggyback structure.
Realistic Example
Home price: $400,000. First mortgage: $320,000 (80%). Second mortgage/HELOC: $40,000 (10%). Your down payment: $40,000 (10%). Result: no PMI on the first loan because the first loan is exactly at 80% LTV. Monthly savings vs. putting 10% down with PMI: approximately $100–$160/month.
Disclaimer: This calculator is for educational purposes only and does not constitute financial or mortgage advice. Consult a licensed mortgage professional for figures specific to your situation.
Sources
- Consumer Financial Protection Bureau — Mortgages
- U.S. Department of Housing and Urban Development (HUD) — Buying a Home
- Fannie Mae — Mortgage Resources
Watch This Next
Free Download
Get the From-Zero Money Reset — free
A simple one-page worksheet to find your breathing room, set up your 3 buckets, and automate one thing — in 10 minutes flat. Enter your email and I will send it immediately.
No spam. Unsubscribe any time. Plain-English money tips only.