Everyone talks about house hacking like it's magic. It's not — it's just a financing loophole most people don't use correctly.

Here's the part that actually matters: lenders will count roughly 75% of projected rental income from the units you won't live in toward your qualifying income. That's the entire trick. It's not about being rich or having some special connection — it's about buying a 2-4 unit property (or a house with rentable rooms) with an owner-occupant loan (as low as 3.5% down FHA) instead of a 20-25% down investor loan.

The number that decides if a deal is good isn't cap rate or appreciation. It's this:

Your mortgage (P&I) + taxes + insurance + maintenance reserve − rent from units you don't occupy = your real monthly housing cost.

If that number is at or below what you'd pay to rent a comparable place solo, the deal is worth digging into further. Most people skip this and just "feel out" a deal — that's how people end up house-poor instead of house-hacked.

Run this math on the next multi-unit listing you see. You'll be surprised how often it pencils out.