Jumbo Mortgage Calculator

Where the jumbo line actually falls

A jumbo loan is not a product, it is a size: any loan above the conforming limit that Fannie Mae and Freddie Mac will buy. For 2026 that baseline is $832,750 for a one-unit home, up $26,250 from 2025. High-cost counties sit above the baseline, capped at 150% of it — $1,249,125 — so where you buy changes whether you are jumbo at all.

Here is the consequence that matters: the line is not a cliff for your whole loan. Borrow $880,000 and the first $832,750 is priced like any conventional mortgage. Only the extra $47,250 — 5.4% of the loan — carries jumbo pricing and stricter underwriting. That is the number to negotiate around, and it is the one this calculator leads with.

What the jumbo label costs

Two things change once you cross the line, and only one of them shows up in your payment:

• Rate. Jumbo money is funded differently, so it carries a spread — in the default example, 6.75% against 6.5% for the conforming quote. In some markets jumbo rates come in below conforming; the only way to know is to ask for both on the same day.
• Underwriting. This is where most jumbo applicants actually get stuck. Expect higher credit score floors, a debt-to-income cap in the low 40s, a second appraisal on large loans, and cash reserves covering six to twelve months of payments after you close. None of that appears in a monthly payment figure, and none of it is modeled here.

Splitting the loan: the piggyback

The standard move around a jumbo loan is to keep the first mortgage inside the limit and put the excess in a second lien — the old 80-10-10 structure, in a jumbo-sized version. On the default numbers:

The saving on the monthly payment is only $6.10 — the second lien is on a 15-year clock, so it amortizes fast — but the lifetime interest difference is $81,040, because $47,250 stops costing 6.75% for thirty years and starts costing 7.5% for fifteen. After that fifteenth year the payment drops to $5,263.55.

Splitting is not free money. Two loans means two sets of closing costs, a second lien that shows up in the county records, and a second that is usually priced as a second — worse than the first even when it is smaller. And it only helps while the jumbo slice is small. Push the same scenario to $1,300,000 and the jumbo portion becomes $207,250: the split now costs $439 a month more than the single jumbo loan, because the expensive second lien has grown to a quarter of the loan.

What moves the answer

• The gap between the two rates. A wide jumbo spread makes splitting attractive; if your jumbo quote matches the conforming one, there is nothing to arbitrage.
• How far over the line you are. $20,000 over is easy to carve off. $300,000 over is not.
• The second lien's term. A 15-year second front-loads the saving into higher monthly cost; a 30-year second barely saves anything at all.
• Your county's limit. In a high-cost county the same $880,000 may not be jumbo in the first place — look your county up before you restructure anything.
• How long you will keep the loan. The interest saving accrues over decades; if you will move in four years, compare closing costs instead.

Common mistakes

• Assuming the whole loan is jumbo-priced. It is not. Only the excess is.
• Comparing one jumbo quote to one conforming quote from different days. Rates move daily; get both the same afternoon.
• Forgetting the reserve requirement. A buyer who can afford the payment can still fail jumbo underwriting on cash reserves.
• Ignoring PMI below 20% down. Jumbo loans with small down payments usually carry mortgage insurance on top — the PMI calculator covers that piece.

How to use this calculator

1. Enter the home price and your down payment.
2. Enter the jumbo rate you were quoted and the conforming rate for a loan at or under the limit.
3. Check the conforming limit against your county — edit it if you are in a high-cost area.
4. Enter the second-mortgage rate and term your lender quoted.
5. Read the jumbo portion first, then the monthly and lifetime differences between the single loan and the split.

Frequently asked questions

What is a jumbo loan in 2026?

Any mortgage above the conforming loan limit — $832,750 for a one-unit home in most of the country, and higher in designated high-cost counties up to $1,249,125. The limit is set annually by FHFA.

How much over the limit can I go?

There is no ceiling on the loan itself, only on the conforming part. What changes above the line is the rate you are offered and how strictly the file is underwritten, not whether a lender will make the loan.

Is a jumbo rate always higher?

No. Jumbo rates track a different funding market and sometimes price below conforming, especially for large loans with strong borrowers. That is why the calculator asks for both rates instead of assuming a spread.

Does splitting into two loans hurt my credit or my closing costs?

You will usually pay two sets of closing costs and carry a recorded second lien. The credit impact is the same hard-inquiry-and-new-account effect you would get from any second mortgage.

Do jumbo loans require mortgage insurance?

Not because they are jumbo. Below 20% down, a jumbo loan generally carries private mortgage insurance the same way a conforming one does; at 20% down or more, neither does.

What reserves do jumbo lenders want?

Commonly six to twelve months of full housing payments in documented liquid assets after closing, on top of the down payment and closing costs — stricter than conforming guidelines.

Data sources: The 2026 conforming loan limit of $832,750 and the 150% high-cost ceiling of $1,249,125 come from the FHFA announcement of conforming loan limit values for 2026 (fhfa.gov, checked 2026-10-23); the field is editable because county-level limits differ and change every year. Payments use the standard amortizing loan formula at the rates you enter, with the second mortgage amortized over its own term. Property tax, insurance, and HOA are added only to show the full monthly outlay; they are identical on both structures. Closing costs, lender fees, mortgage insurance, and jumbo underwriting requirements are not modeled, and every figure here is an estimate rather than an offer or financial advice — compare written Loan Estimates before you choose. All calculations run in your browser. For the escrow breakdown see the taxes and insurance calculator; for the month-by-month view, the amortization schedule calculator.