Mortar

About

Mortar turns any Zillow for-sale listing into a rental investment analysis in under 10 seconds.

Open a listing on Zillow, click the Mortar icon, and Mortar reads the property details straight off the page, including price, beds, baths, square footage, address. Then it runs the numbers a buy-and-hold investor cares about.

What you see:
- Monthly cash flow
- Cap rate
- Cash-on-cash return
- Gross rent multiplier (GRM)
- A triage verdict: BUY / INVESTIGATE / PASS with a plain-English reason
- Estimated ARV (automated value estimate, not an appraisal)

Rent source:
When Zillow publishes a Rent Zestimate on the listing, Mortar uses it directly. When it doesn't, an AI model estimates market rent as a fallback. The rent figure is always editable; type in your own number and all metrics recalculate instantly.

How the math works:
All investment metrics are computed deterministically from a fixed set of assumptions (20% down, 7.5%/30-yr mortgage, national-average tax and insurance). The AI never does arithmetic, it only estimates rent and value when Zillow's own figures aren't on the page. This means the numbers are consistent and reproducible, not hallucinated.

Disclaimer: Estimates only. Not financial advice, not an appraisal. Verify before you offer.

Who it's for:
Buy-and-hold rental investors, BRRRR investors, house hackers, and anyone screening single-family or small multifamily listings who wants a fast read before committing time to a deep underwrite.

Free tier:
Five free analyses, no credit card required.

Subscription:
Unlimited analyses for $29/month. Billing handled by LemonSqueezy. Your card details never touch Mortar's servers. Cancel anytime.

Privacy:
Mortar only runs on Zillow listing detail pages. It does not track your browsing, show ads, or sell your data. Mortar is not affiliated with Zillow. Full privacy policy: https://mortar-website.vercel.app/privacy