How to use Undrly, start to finish.

Written for someone looking at their first rental deal. Ten minutes here and the panel will read like a second language.

Where the panel appears (and where it doesn't)

Undrly activates on for-sale listing pages on Zillow and Realtor.com — houses, condos, townhomes, and small multi-family. Open any listing and the panel builds itself from that listing's real price, taxes, and facts. Condo or HOA property? The disclosed HOA fee is read from the listing and included in the monthly math.

It deliberately stays quiet on search results, apartment-community rental pages, and anything you can't actually buy — no listing to underwrite, no panel. If you expected it on a page and don't see it, check that it's a for-sale listing first, then refresh once.

Start at the top: the verdict and the score

The stamp is the panel's one-glance answer, and it is deliberately blunt:

• STRONG SOLID — the deal genuinely makes money after all costs, including the ones listing sites skip (vacancy, maintenance, reserves).
• CLOSE STRETCH — roughly break-even to mildly negative. Not doomed — a price negotiation or higher rent could flip it — but not a deal yet.
• PASS — loses meaningful money every month at this price. The stamp exists because most tools won't say this.

The 0–10 score under it is the same judgment with more resolution, and the percentile line ("better than 71% of properties you've viewed") builds as you browse — it's how your own eye calibrates to your market.

The six numbers, in plain English

Hover any label in the panel for a definition. The short version:

• Monthly cash flow — what's left each month after the mortgage, taxes, insurance, vacancy allowance, and maintenance reserve. The headline number. Positive means the property pays you.
• Cap rate — the property's return ignoring your loan. Useful for comparing buildings to each other.
• Cash-on-cash — yearly cash flow divided by the actual cash you put in. This is your return, and it's what drives the verdict. Compare it to the ~4% you'd earn doing nothing in treasuries.
• Monthly PITI — principal, interest, taxes, insurance. Note: tax is re-estimated at your purchase price, not the seller's old bill — the #1 rookie underwriting mistake, handled.
• Break-even rent — the exact rent where cash flow is zero. If nearby comps can't reach this number, no amount of optimism will.
• Cash to close — down payment + ~3% closing costs + 3 months of reserves. The real check you'd write, not just the down payment.

"What this could rent for" — the rent ladder

Rent is the biggest unknown in any deal, so instead of pretending one number is right, the ladder shows three, drawn from real nearby rental listings (same property type, same bedrooms, outliers trimmed):

• Conservative / Likely / Optimistic — the 20th, 50th, and 80th percentile of the comps, each showing the cash flow it produces. Tap a rung to apply it.
• When enough comps publish square footage, the estimate is size-adjusted ($/sqft × this home's size) — the caption says so when it happens.
• The caption always names the basis honestly: how many comps, what matched, what didn't.

Seller position: your negotiation read

Expand the "Seller position" row and the panel reconstructs the other side of the table from public records: what they paid, when, their estimated equity at your offer price (modeled from typical financing in their purchase year), and their rough walk-away cash. A seller with 18 years of equity can take a low offer; one who bought two years ago often mathematically can't. Pair it with the "days on market" tag above it and you know how hard you can push.

Flags: what's buried in the description

The Flags tab scans the listing's own text for things that change the math or the risk — as-is sales, roof age, land leases, flood mentions, special assessments, but also good news like new systems. Each flag quotes the exact sentence it found, so you judge the source yourself. It reads negations correctly ("Land Lease: No" won't flag), and it's a reading assistant, not a substitute for reading.

Assumptions: make the model yours

The defaults are honest, commonly-cited investor numbers — but they're defaults. The two worth personalizing immediately:

1. Down payment (the slider is right on the summary) — at 20–25% most deals look very different than at 5%.
2. Insurance — the panel estimates from state averages and says so. A real quote (the Resources tab links a quoting tool) is the single best accuracy upgrade you can make.

Everything else — vacancy, maintenance reserve, and in Short-Term mode the platform fee, cleaning economics, and furnishing budget — lives in the Assumptions tab with honest defaults explained.

Short-Term mode (Airbnb math) — the Pro side

The Long-Term/Short-Term toggle at the top switches the entire model to nightly-rate economics. Free users can open it and see the structure; the numbers unlock with Pro, because they run on licensed market data that costs real money per lookup. With Pro:

• Check this market pulls 25 comparable short-term rentals around the listing: real nightly rates, occupancy, revenue, fees, and competition — 16 stats.
• Rate tiers (Below / Typical / Above) show the strategy trade-off: price low and book more nights, or price high and book fewer — each with its own cash flow.
• Your plan includes 50 market checks a month, and re-checking a property you've already pulled is always free.

Here's what one market check looks like — this example is live, so tap the rate tiers:

Sample market. On a real listing these are the trailing-twelve-month numbers for 25 comparable Airbnbs around that address.

How to read it as a beginner: RevPAR is the one-number summary (rate × occupancy — what a night is really worth here). The tiers are the strategy choice: budget pricing books more nights, premium books fewer — and in the extension, each tier shows the cash flow it produces. Adjusted occupancy haircuts part-time hosts who block their slow season, so you're not fooled by inflated raw numbers. And the competition rows tell you what you'd be up against — a market that's 44% professionally managed is not a hobbyist market.

That's what a market check buys. If short-term is your plan, Pro is $14.99/mo — and if it isn't, everything else on this page stays free forever.

The Saved tab: build a shortlist

Hit ☆ Save on any listing and it joins your list with its score chip and cash flow attached. Sort by score, cash flow, or cash-on-cash. A week of browsing becomes one screen where the green rows rise to the top — that's your "actually go look at these" list. Saves live on your device.

A sensible first workflow

1. Browse fast, trust the stamp. Don't analyze every listing — let PASS save you from spreadsheets that were never going to work.
2. On anything CLOSE or better: tap the conservative rent rung. Still standing? Save it.
3. On your saved greens: test your real offer price in the price box, check the seller position for negotiating room, read the flags.
4. Before any offer: verify the two estimates — a real insurance quote, and the county's actual tax rate. The panel marks what's verified vs estimated so you know exactly what to check.
5. Then the humans take over: inspection, agent, lender. Undrly's job was getting you here in seconds per listing instead of an evening each.

Plain-English glossary

Questions the panel doesn't answer? support at undrly dot app — it goes straight to the person who builds it.