This jumbo mortgage calculator shows the monthly payment with estimated property tax, whether the loan passes the 2026 limit of $832,750, and the liquid money a lender may ask to see. A $2M Lower Merion home with 20% down at 7.40% comes to about $13,423 a month and about $590,270 in liquid money at 12 months of reserves. Jumbo loans in Pennsylvania has the full requirements.
You're buying a Main Line home above about $1M with a mortgage and want the payment and the cash before you talk to a lender.
How the jumbo mortgage calculator works
It takes the price and down payment to find the loan, tests it against the limit, then works out principal and interest. It adds estimated property tax for the township, and sums the down payment, fixed closing lines and reserves.
The rate to enter
The default is Freddie Mac's weekly 30-year average, which tracks conforming loans. Jumbo quotes can sit above or below it, so replace it with your lender's quote.
Reserves
Reserves are months of payment you still hold after closing. Lenders set the number by loan size, so ask for it in writing. The money stays yours, but it has to exist.
When a mortgage becomes a jumbo mortgage on the Main Line
In Montgomery, Delaware and Chester counties a one-unit loan above $832,750 is a jumbo loan in 2026. At 20% down that starts at a price of about $1,040,938. FHFA has not yet published the 2027 limits.
Cash to show at common prices
| Price | Monthly P&I at 7.40% | Liquid money, 12 months | Liquid money, 24 months |
|---|---|---|---|
| $2M | $11,078 | $590,270 | $751,346 |
| $3M | $16,617 | $883,088 | $1,124,701 |
| $5M | $27,695 | $1,468,723 | $1,871,412 |
These use 20% down and estimated Lower Merion property tax.
The closing lines here come from the PA closing cost calculator and the tax from the property tax calculator.
Jumbo mortgage calculator FAQs
What counts as a jumbo mortgage in Pennsylvania?
On the Main Line, a one-unit loan above the 2026 limit of $832,750 in Montgomery, Delaware and Chester counties.
Does the payment include insurance?
No. Insurance varies too much by house to estimate, so get a quote for the specific home and add it.
Why is the rate only a benchmark?
Freddie Mac's survey tracks conforming loans. Use your lender's jumbo quote once you have one.
How many months of reserves do I need?
It depends on the lender and the loan size. The calculator defaults to 12 months so you can see the effect; ask each lender for its rule in writing.
Is anything I type saved?
No. The calculator runs in your browser and nothing is saved or sent.
Sources
Reviewed by Reid Rosenthal
Reid reviewed this page for accuracy on November 5, 2026. Figures come from the sources listed above. Our research process.
Reid Rosenthal is a luxury real estate agent on the Philadelphia Main Line and an Associate Broker who leads The Rosenthal Group at BHHS Fox & Roach, Realtors. RealTrends Verified ranks the team #4 in Philadelphia by sales volume, with $131.59 million across 179 sales in 2025.
- $131.59MTeam sales in 2025, RealTrends Verified
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The Rosenthal Group, Berkshire Hathaway HomeServices Fox & Roach, Realtors, 112 S 19th St, Suite 200, Philadelphia, PA 19103. Office (215) 546-0550. Pennsylvania license AB068320. General information, not legal, tax or lending advice.
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