Down Payment on a Second Home

Written by Bryan Piccolomini, NMLS #228509, a mortgage loan originator with Residential Mortgage, LLC (NMLS #167729), a wholly owned subsidiary of Northrim Bank. Loans are originated through Residential Mortgage, LLC.

Why nobody can quote you one number

Down payment is expressed in underwriting as loan-to-value, the size of the loan against the value of the property. Fannie Mae publishes maximum loan-to-value ratios by occupancy type in its Eligibility Matrix, a document incorporated by reference into the Selling Guide, and the limits for a second home are not the same as the limits for a primary residence. The current matrix, dated August 2026, lists 90% as the maximum loan-to-value for a one-unit second home purchase, which works out to a 10% minimum down payment on a conforming loan underwritten to Fannie Mae’s guidelines. That is the floor for that loan type, not a quote: the matrix itself notes exceptions, pricing differs by file, and jumbo, non-QM and portfolio programs set their own terms. On top of that sit the automated underwriting decision, the property type, and the rest of your file. Two buyers looking at the same house can land in different places.

So the honest answer to "how much do I need down" is that it depends, and the useful answer is a range you have modeled yourself.

Source: Fannie Mae Selling Guide, Eligibility.

Model it before you ask

The down payment calculator takes a purchase price and a scenario you pick and returns the down payment and the amount financed. It recommends nothing. It just does the arithmetic on numbers you supply, so you can see the shape of several options side by side.

Run the price you are actually considering, not a round number. Then run one above it and one below it. The spread between those three results is the real decision.

Gift money and reserves

Two adjacent rules from the same guidelines are worth knowing. Fannie Mae’s Selling Guide permits personal gift funds on a second home; where the loan-to-value is above 80%, the borrower contributes 5% from their own funds before gifts cover the rest. And loans underwritten through Desktop Underwriter carry a reserve requirement of at least two months on a second home transaction, meaning at least two months of the full housing payment left over after closing; Desktop Underwriter can call for more depending on the file. Both are program rules, not Bryan’s terms, and both have exceptions by file.

What the down payment does not cover

The figure the calculator returns is the down payment against the purchase price. It is not the cash you need at the table. Closing costs, prepaid taxes and insurance, and any reserves the program calls for sit on top of it. Buyers who plan to the down payment alone are the ones who get surprised late.

Reserves, briefly

Reserves are months of housing payments you can still cover from assets after closing. A second home file is reviewed with two properties in mind rather than one, so reserves come up more often than they do on a primary residence purchase. The requirement for a specific file comes out of the program and the underwriting findings.

Where the money comes from matters as much as the amount

Down payment funds have to be documented and sourced. In practice that means an underwriter can trace where the money came from and satisfy themselves it is yours and not borrowed. Two things slow files down here more than anything else:

• Recent transfers between accounts. Every hop needs a statement. Moving money around in the month before application creates work.
• Deposits without an obvious origin. Anything that is not payroll usually needs an explanation and a paper trail.

If the plan is to use the equity in the home you already own, that is a specific route with its own mechanics. The equity guide covers it.

The number that actually decides the file

Down payment gets the attention, but the constraint that stops more second home purchases is the debt-to-income comparison, because your existing mortgage payment counts in full alongside the new one. Before fixing on a down payment target, it is worth running the debt-to-income picture as well.

Common questions