About HomeDealMath

I run more than 200 rental units across New England. I've been a landlord for 15+ years, mostly while holding a full-time engineering career. I built this site because every other rental calculator I found was either oversimplified (just a mortgage calculator with one extra field) or wrapped behind a $20/month subscription. Both are wrong for the moment when most landlords actually need a calculator: 11pm the night before submitting an offer, trying to figure out if a deal really cash-flows.

Why this site is free

The site exists because the calculators I wanted didn't exist — and because the marginal cost of running a static site is basically zero.

If a calculator helps you avoid a bad deal — or buy a good one — forward it to one specific person who'd benefit. That's the only "growth strategy" running here.

How the defaults are set

Every calculator has pre-filled defaults pulled from my actual operating data on a 200+ unit New England portfolio. Maintenance reserves, vacancy rates, operating expense ratios — those aren't made-up rules of thumb. They're what I actually spent last year, normalized across the portfolio. Your numbers will vary based on market, asset class, and management approach. The defaults are starting points, not gospel.

What's missing

Currently no 1031 exchange calculator, depreciation calculator, or refinance comparison tool. Those will land eventually. The site is intentionally Tier-1-only at launch — better to ship 10 calculators that work well than 22 that mostly work.

Bugs / suggestions

If a number looks off or a calculation seems wrong, please tell me. I'd rather fix bugs than ship more features.