Most families around the country who have small children tend to live in their first home, or start-up home, for approximately 7 years.  Then, its common for those families to look at expanding or moving up to a larger home.  It’s families like this, known as move up buyers, that Zillow recently studied to determine what the cost implications of “moving up” might be.

Zillow found there are two determining factors that determine the costs of moving up…size and location. Let’s look at home size first.  Let’s say that you’re moving from a two bedroom house to a three bedroom house in the same zip code.  The average increase nationwide in extra mortgage costs would be $447 per month or $5,300./yearly.  The average increase nationwide in extra mortgage costs from a one bedroom home to a two bedroom home would be $192 per month or $2,244./yearly.  The average increase nationwide in extra mortgage costs for a three bedroom to a four bedroom would be $614 per month or $7,368./yearly.

Now, let’s look at location.  In the Midwest, move-up buyers will get more bang for their buck.  Instead of paying the nation’s average of $447. more a month, move up buyers in Chicago, Cincinnati, Cleveland, Philadelphia, Indianapolis and St. Louis will pay less, approximately $150.00 more monthly.  Move up buyers in popular coastal markets can expect to pay an additional $500 per month and those in sizzling hot markets such as Los Angeles, San Francisco and San Jose can anticipate increased mortgage costs of approximately $1,000 to $2,244 per month.

Here’s a look at approximate increased monthly mortgage costs in 25 metro markets:

New York City – $302 (a bargain)                                     Seattle –              $574

San Jose –       $2,224                                                      San Francisco –   $1,660

Denver –           $601                                                       Los Angeles –      $1,033

Miami –             $599                                                       Boston –             $512

Detroit –            $280                                                       Portland –           $497

Minneapolis –      $252                                                      Charlotte –          $224

Washington DC –  $429                                                     Pittsburgh –        $198

San Antonio –       $198                                                     Austin –              $372

Chicago –             $144                                                     St. Louis –           $155

Dallas –               $365                                                       Kansas City –     $113

Las Vegas –          $357                                                   Baltimore –           $105

Philadelphia –        $77                                                      Cleveland –         $74

Phoenix –              $302

These numbers were compiled by Zillow Analysis of Estimates and the U.S. Census Bureau in its American Community Survey.