What counts as a primary residence for U.S. expat tax purposes, and why does it matter?
Your primary residence for U.S. tax purposes is the home where you live most of the year and treat as your main home. It determines state residency, eligibility for the Section 121 home sale exclusion ($250,000 single, $500,000 MFJ), foreign housing deductions, and mortgage interest allocation.
The IRS looks at factors including:
- Where do you spend the most time during the year
- Where are your belongings and personal items
- Where you hold a driver’s license, voter registration, and bank accounts
- Where family members live
- Where utility bills and mail are sent
Why it matters for expats:
| Tax concept | Primary residence impact |
| State residency | Keeping U.S. primary residence often keeps you a state resident |
| Section 121 exclusion | Must have owned and used as primary residence 2 of last 5 years |
| Foreign housing deduction | Your foreign primary residence unlocks Form 2555 housing cost exclusions |
| Mortgage interest | Up to 2 primary/second homes, total $750,000 debt cap (post-TCJA) |
| FEIE tax home | Primary residence abroad supports a foreign tax home |
Expats with both a U.S. home and a foreign home:
- Cannot have two primary residences simultaneously
- Should pick which home is primary based on time, ties, and documentation
- May qualify for Section 121 at sale of U.S. home if still within the 2-of-5 use window
- Second home (the non-primary) gets limited deductions for mortgage interest
Declaring a foreign home as your primary residence typically helps with FEIE but may complicate Section 121 planning if you later sell the U.S. home.
For strategy on primary residence decisions, see our Buying and Selling Real Estate Abroad guide. If you own property overseas, Greenback helps foreign property owners report rental income, capital gains, and housing exclusions correctly.
Last updated on April 29, 2026
