For Peninsula Buyers

Jumbo Loan Calculator

Enter your purchase price and down payment to find out whether your loan requires jumbo financing — and what that means for qualification and rates.

San Mateo & Santa Clara Counties

Is this a jumbo loan?

Loan Classification
Loan Amount
2025 High-Cost Conforming Limit (San Mateo / Santa Clara)$1,089,300
Amount Over Conforming Limit
Loan-to-Value Ratio
Typical Down Payment Required (Jumbo)
The FHFA conforming loan limit for high-cost areas is adjusted annually. Verify the current limit with your lender or at fhfa.gov. Jumbo underwriting standards vary significantly by lender — consult a licensed mortgage professional for qualification guidance. Lisa M. Lum and Coldwell Banker Realty provide this calculator for informational purposes only and do not provide mortgage advice.

Jumbo Loans on the Peninsula

What is the conforming loan limit for San Mateo and Santa Clara counties?

San Mateo and Santa Clara counties are FHFA-designated high-cost areas. For 2025, the conforming loan limit in these counties is $1,089,300 for a single-unit property — significantly higher than the national baseline limit of $806,500. Any loan amount above $1,089,300 is a jumbo loan and cannot be sold to Fannie Mae or Freddie Mac. Check the FHFA website for the most current year's limit, as these are adjusted annually based on home price indices.

What makes a jumbo loan different from a conforming loan?

Conforming loans are purchased by Fannie Mae or Freddie Mac after origination, which gives lenders certainty of a secondary market exit and allows them to offer competitive rates with relatively flexible underwriting. Jumbo loans stay on the lender's books or are sold to private investors — which means lenders apply stricter qualification standards: typically 720+ credit score, 12+ months cash reserves after closing, lower debt-to-income ratios (usually 43% or below), and often a larger down payment requirement. Rates can be higher, lower, or similar to conforming depending on market conditions and lender competition.

How much down payment do I need for a jumbo loan on the Peninsula?

Jumbo lenders on the Peninsula typically require 20% down for loans up to $3M, and 25-30% for loans from $3M to $5M. Above $5M, most private banks want 30-40% down or underwrite based on total asset picture rather than loan-to-value alone. Some lenders will do 10% down jumbo at higher rates, but options narrow above $2M. Peninsula buyers with significant RSU income should work with a lender experienced in tech compensation — the treatment of unvested stock and ESPP can make a meaningful difference in qualification.

Should I split my loan to stay under the conforming limit?

A piggyback loan structure (80/10/10) splits financing into a conforming first mortgage at the limit and a second mortgage for the remaining amount. This can make sense when the conforming rate is meaningfully better than the jumbo rate and the second's rate doesn't offset the savings. On the Peninsula, where purchase prices often exceed $2M-$3M and the second would be large, the math is less often favorable than in moderate-cost markets. A good mortgage broker will model both scenarios — never assume the split structure is always better.

Ready to get pre-approved?

Lisa works with lenders who specialize in Peninsula jumbo loans — including portfolio lenders who underwrite RSU and deferred compensation income. She can make an introduction.

Connect with a Jumbo Lender