Decide if a rental is worth buying — in minutes.
BuyBox runs the full underwrite — mortgage, NOI, cap rate, cash-on-cash, DSCR and BRRRR refinance math — then tells you, against your own criteria, whether a deal is in your buy box.
iHover any number to see the formula. No black box.
Also available for Windows ↓
7-day free trial·Full premium access·No credit card required
one-click import
rent comps Computes locally, syncs encrypted when you're onlineFrom a listing to a verdict in three moves.
Most deals die in the first two minutes. BuyBox gets you to a yes-or-no fast, then goes as deep as the good ones deserve.
Every number shows its work.
Real estate math shouldn't be a black box. Hover over any term for a plain-English definition, then open the proof to watch a metric build from rent and expenses — step by step — to the figure you're betting on.
New to underwriting? Start with the verdict and the basics are right there. Been at it for years? The full derivation is one tap away. The same tool grows with you.
One tool that does the underwriting, exceptionally well.
The full metric stack
Every number that decides a deal, computed the industry-standard way.
BRRRR refinance, done right
Model the bridge, the rehab hold and the DSCR cash-out refi. See exactly how much capital you pull back out — including the infinite-return scenario when you leave nothing in.
30-year projections
Rent growth, appreciation, expense creep and loan paydown — year by year, with a hypothetical-sale return at every exit.
Your deals on every device
Deals are computed on your own device and saved to your account — encrypted in transit and at rest. Start on the laptop, finish on the desktop.
Chrome extension
Capture any Zillow, Realtor.com or Redfin listing in one click and send it straight to a pre-filled Quick Analysis.
Lender-ready export
One click produces a two-tab Excel workbook with live formulas and a full amortization schedule — ready to hand to your lender.
Set the rules once. Score every deal against them.
A buy box is the set of thresholds that define which deals you'll buy and which you won't. Dial in yours — DSCR floor, minimum cash-on-cash, max price-to-ARV — and BuyBox judges every property against your standard, not a generic one.
Explore the analysis engine →An audited engine, your data under your control.
Every metric is computed the industry-standard way and shows its full derivation. Your deals compute locally and sync encrypted — nothing is locked in, nothing is hidden.
What BuyBox does — and doesn't.
Do I need to install anything?
No — BuyBox runs in your browser, so you can underwrite your first deal in seconds. Prefer a dedicated app? An optional Windows desktop app is included — same account, same data.
Does it actually tell me whether to buy?
It scores every deal against your buy box — the DSCR floor, cash-on-cash minimum and price-to-ARV cap you set — and marks each metric strong, workable or below. The verdict is against your criteria, not a generic benchmark.
Where do the numbers come from — can I trust them?
You control every input. Listing details pre-fill from the address, rent comps come from Rentometer, and every metric shows its full derivation — hover any number for the formula. Nothing is hidden behind the scenes.
Can it handle a BRRRR or refinance?
Yes. Model the bridge loan, rehab hold and DSCR cash-out refi — including the infinite-return case where you pull all of your capital back out — then project the hold for up to 30 years.
Can I get the analysis out of BuyBox?
One click exports a two-tab Excel workbook with live formulas and a full amortization schedule — ready to hand to a lender or partner. Your data is never locked in.
Is my data private?
Your deals are encrypted in transit and at rest, isolated to your account, and never sold or used to train models. The analysis itself runs on your own device, not on our servers. You’ll need to be signed in to save your work.
Trials, billing and refunds? See pricing questions →
Coming from RealData? You're in the right place.
RealData retired its analyzer in 2026. BuyBox keeps the part that mattered — serious underwriting you can own outright — and is honest about what it doesn't do.