Every breakdown stops at closing costs, so what does a duplex cost to run

For one tenant next door you don't need software, you need a lease that holds up and a way to take rent that leaves a record. The free platforms exist and they mostly work by charging the applicant the screening fee directly, usually in that 35 to 55 range. Where I'd spend actual money is on a state-specific lease form rather than a generic download.

Solder has the shape of it right. Here's the running list for a two-unit owner-occupied setup.

Tenant screening, meaning credit report, background check, eviction history, commonly runs 35 to 60 per applicant. Several online platforms pass that cost to the applicant, which is legal in most places but a few states cap what you can charge for an application fee, so check your state's rule before you set it.

Rent collection and light management software is usually free to landlords with a handful of units, with the platform earning on payment processing or tenant fees. Paid tiers tend to start around 15 to 30 a month per portfolio and buy you things like maintenance ticket tracking and accounting exports. For one tenant on the other side of a wall, free is normally enough.

A state-specific lease costs anywhere from nothing through a local landlord association membership to a few hundred dollars from an attorney. Landlord associations often run 100 to 250 a year and the forms and local guidance are usually the reason people join.

Accounting software, if you want the rental books separate from your personal money, runs roughly 15 to 40 a month.

On the license question, some cities and counties require a rental license or registration for any unit you rent out, sometimes with an inspection, and this varies by state and often by municipality. Fees are frequently in the 50 to 200 per unit per year range where they exist. Call your city or county housing department and ask directly, because operating an unlicensed unit where registration is required can cost you the ability to enforce a lease or evict.

The cost people forget entirely is insurance. A duplex you partly rent needs a different policy than a plain homeowner's policy, and that's a real annual number worth quoting before you commit.

The landlord license thing is genuinely regional. Two metros I looked at had nothing at all, and a third required registration plus a paid inspection every two years before you could rent a single unit. It's not something you can research generically, which is annoying when you're comparing markets on a spreadsheet.