What is a real estate buy box? The definitive guide, with a fill-in template

Have you ever fallen in love with a house at 11pm?

You know the feeling. The photos are gorgeous, the price looks low, and by midnight you have mentally painted the kitchen. Then you run the numbers in the morning and your stomach drops.

That is exactly what a buy box exists to stop. We built BuyBox around this one idea!

If you order the wrong pizza, you eat it anyway. If you buy the wrong shoes, you return them. If you pick the wrong movie, you lose two hours. However… if you buy the wrong rental, you could be feeding it $400 a month for YEARS.

Why do you need a buy box at all?

Short answer: speed and sanity.

Think of it like a grocery list. Walk into the store hungry without one and you leave with three bags of chips and no dinner. Walk in with the list and you are out in ten minutes with exactly what you came for.

Your buy box does three jobs for you:

1. It kills bad deals fast. You stop “analyzing” deals that were never going to work.
2. It protects you from yourself. The 11pm crush has to get past rules you wrote while calm.
3. It tells agents and wholesalers what to send you. A clear box gets you better deal flow, because people know what a yes looks like.

Here is the part most people miss: there is no universal “right” buy box. Two investors can look at the same duplex and both be correct, because one wants monthly cash flow and the other wants long-term equity.

Your box. Your rules!

The two halves of every buy box

Let me simplify. Every good buy box has two halves:

• The filter half: what kinds of properties you even look at (market, price, property type, condition).
• The math half: the minimum numbers a deal must hit to earn a yes (cap rate, cash-on-cash, DSCR, the 1% rule, cash left in a BRRRR, and friends).

The filter half saves you time. The math half saves you money. You need both!

The filter half: where, what and how rough

Market

Where will you buy? Be specific. “Ohio” is not a market. “Single-family homes in three ZIP codes I can drive to in 30 minutes” is a market.

Ask yourself:

• Can you (or a manager you trust) actually reach this property when the water heater dies?
• Do you know what rents really are on these streets, not just what a listing claims?
• Is this a place you understand well enough to spot an overpriced deal?

Price range

Your price range comes from your cash and your financing, not from your hopes. Work backward: how much cash can you put in (down payment, closing costs, repairs, reserves), and what loan will a lender actually give you?

Property type

Single-family? Small multifamily (duplex, triplex, fourplex)? Condos? Each one behaves differently. Small multifamily spreads vacancy risk across doors, while single-family is often easier to sell later.

This choice matters for the math half too (we’ll explain in a second).

Condition

How much work can you handle? Be honest here. “Cosmetic only” (paint, floors, fixtures) is a very different business from “needs a roof, a furnace and a prayer.”

Your condition rule should match your rehab budget, your contractor bench and your nerves.

The math half: the numbers a deal has to hit

This is where most buy boxes go soft. “Good cash flow” is not a rule. “$200 per door per month after every expense” is a rule.

Here are the metrics investors use most, what each one tells you, and the starting points BuyBox ships with by default. (These defaults are a starting point, not gospel. You change them to match your strategy.)

The 1% rule (rent-to-price)

Monthly rent divided by purchase price. A $150,000 house renting for $1,500 a month is exactly 1%.

It is crude. We like it anyway, because our view is simple: it takes five seconds and kills obvious losers. BuyBox grades rent-to-price as good at 1.0% or higher, workable from 0.8%, and bad below 0.8% by default.

Cap rate

Net operating income (rent minus operating expenses, before your mortgage) divided by the purchase price. Cap rate tells you how hard the property works on its own, ignoring your loan entirely.

BuyBox default: good at 8% or higher, workable from 5%, bad below 5%.

Cash-on-cash return

Your annual cash flow (after the mortgage) divided by the cash you still have in the deal. On a straight purchase, that is every dollar you put in. This is the “what is MY money earning” number.

BuyBox default: good at 8% or higher, workable from 5%, bad below 5%.

DSCR (debt service coverage ratio)

Net operating income divided by your annual mortgage payments. A DSCR of 1.25 means the property earns 25% more than the loan payment.

Under 1.0? The property cannot cover its own mortgage. You cover it. Every month.

BuyBox default: good at 1.25 or higher, workable from 1.0, bad below 1.0. DSCR is one of the metrics BuyBox treats as critical (more on that below).

Cash flow per door

Monthly cash flow after every expense and the mortgage, divided by the number of units. BuyBox uses separate targets for single-family and small multifamily:

• Single-family default: good at $300 or more, workable from $200, bad below $200.
• Duplex, triplex or fourplex default: good at $200 or more per door, workable from $100, bad below $100.

That is why property type matters for the math half. Pick the type and the right target follows.

Break-even occupancy

What share of the year the property must be rented just to cover expenses and the mortgage. Lower is better, because it means more room for vacancy before you lose money.

BuyBox default: good at 70% or lower, workable up to 85%, bad above 85%.

Percent of ARV (all-in cost vs. after-repair value)

Your total cost (price, buying costs, repairs) divided by what the property will be worth once fixed. Lower is better, because the gap is your equity cushion.

BuyBox default: good at 70% or lower, workable up to 80%, bad above 80%.

IRR

Internal rate of return over your hold period: the one number that blends cash flow, loan paydown, appreciation and the eventual sale. BuyBox default: good at 15% or higher, workable from 10%, bad below 10%.

BRRRR: cash left in the deal

If you buy, rehab, rent, refinance and repeat, the question that decides everything is simple: how much of your cash is still stuck in the property after the refinance?

Leave $0 in and your money is free to do it again. Leave $40,000 in and you have bought a rental the slow way with extra steps.

BuyBox calculates cash left in the deal after the refinance and measures your cash-on-cash and IRR against that number. (There is no separate pass/fail band just for cash left in. You express that rule through your cash-on-cash and % of ARV targets, and you can write a hard dollar cap into your box template below.)

How BuyBox checks a deal against your buy box

Here’s what that means in practice.

In BuyBox, you set your buy box in Settings, then Thresholds (the set your buy box guide walks through it). For each metric you set the “good” and “bad” cutoffs, and the space between them is “workable.” You can tune:

• Rent-to-price, DSCR and break-even occupancy
• Cash flow per door (single-family and small multifamily targets)
• Percent of ARV, cash-on-cash, IRR and cap rate

Then every deal you analyze gets graded against YOUR numbers. Those thresholds drive three things at once: the color on every metric, the risk flags that name what is failing, and the deal score and verdict.

The verdict lands in one of four buckets:

The critical metrics are DSCR and cash flow per door. Fail either one and the deal goes to High Risk on its own, no matter how pretty the cap rate looks. We made that choice on purpose: a deal that cannot pay its own bills is not a deal.

The verdict also names the one or two metrics that decided it, so you know exactly which number to fix (or which deal to walk away from).

Want to skip the retyping? The BuyBox Chrome extension sends a listing from supported listing sites straight into a pre-filled analysis.

A worked example: same rules, three deals

Say you are looking at a single-family rental in your target market. Every figure below comes straight from the BuyBox calc engine (all inputs are in the Appendix).

Deal A: $210,000, rents for $1,850 a month, 25% down at 7% for 30 years, 3% buying costs, 8% management, 6% vacancy, 5% repairs, 5% capital expenses, $110 a month insurance and $230 a month tax.

On paper it rents fine. Against the default buy box?

• Monthly cash flow: $38.13
• DSCR: 1.12 (workable)
• Break-even occupancy: 91.49% (bad)
• Cash-on-cash: 0.78% (bad)
• Rent-to-price: 0.88% (workable)
• Verdict: High Risk, decided by cash flow per door and break-even occupancy

You would put $58,800 of your own cash in to earn $38 a month. Would you take that trade? Not a chance.

Now watch what your buy box does. Say you are an appreciation-focused investor and you loosen three rules in Settings: cash flow per door good at $100 and bad below $0, DSCR good at 1.10 and bad below 1.0, cash-on-cash good at 4% and bad below 0%.

Same deal. Different grades. Cash flow per door moves to workable, DSCR moves to good, cash-on-cash moves to workable. The verdict? Still High Risk, because three metrics are still bad (break-even occupancy, % of ARV and IRR).

Your buy box changed the grades. It did not change the math. That is exactly how it should work.

Deal B: same house, $150,000 price and $175,000 value, same rent and expenses.

• Monthly cash flow: $337.51 (good)
• DSCR: 1.57 (good)
• Rent-to-price: 1.23% (good)
• Cap rate: 9.38% (good)
• Cash-on-cash: 9.64% (good)
• IRR: 14.92% (workable)
• Verdict: Solid Deal, decided by % of ARV (88.29%)

Big improvement! It survives. But by the default box it is not a home run yet, and the verdict tells you why in plain words.

Deal C: a BRRRR. Buy at $150,000 in cash, $30,000 of rehab, four months of holding, refinance at 75% of value, rent at $1,800.

• If it appraises at $220,000: cash left in the deal is $25,370, but monthly cash flow is negative $50.31 because the bigger refinance loan eats the rent.
• If it appraises at $200,000: cash left in the deal climbs to $39,920, and monthly cash flow is $49.49.

Read that twice! The higher appraisal gets more of your money back and turns the rental cash-flow negative. Both versions land at High Risk on the default box. A buy box that only asked “how much cash did I get back?” would have missed it completely.

Your fill-in buy box template

Copy this. Fill in every blank. Tape it above your desk.

MY BUY BOX                                   Date: ____________

FILTER HALF
Market (cities / ZIPs / neighborhoods): ______________________
Max drive time or manager in place: __________________________
Price range: $__________ to $__________
Property types: [ ] Single-family  [ ] Duplex  [ ] Triplex  [ ] Fourplex  [ ] Other: ______
Condition: [ ] Turnkey  [ ] Cosmetic  [ ] Moderate rehab  [ ] Heavy rehab
Max rehab budget: $__________
Strategy: [ ] Buy and hold  [ ] BRRRR  [ ] Other: ______

MATH HALF                     GOOD (at least)   BAD (below)
Rent-to-price (1% rule)       ______ %          ______ %
Cap rate                      ______ %          ______ %
Cash-on-cash return           ______ %          ______ %
DSCR                          ______            ______
Cash flow per door (SFR)      $______           $______
Cash flow per door (2 to 4)   $______           $______
IRR                           ______ %          ______ %

                              GOOD (at most)    BAD (above)
Break-even occupancy          ______ %          ______ %
All-in cost as % of ARV       ______ %          ______ %

BRRRR ONLY
Max cash left in after refi:  $__________
Refi assumption (LTV / rate): ______ % / ______ %

DEAL KILLERS (automatic no, whatever the numbers say)
1. ________________________________
2. ________________________________
3. ________________________________

Not sure what to put in the math half yet? Start with the BuyBox defaults above and tighten them as your strategy sharpens. You don’t need to get this perfect on day one.

You just need to write it down. So go do it!

Frequently asked

What is a buy box in real estate?

A buy box is the written set of criteria a property must meet before you will buy it. It covers where and what you buy (market, price, property type, condition) and the minimum numbers a deal must hit, like cap rate, cash-on-cash return, DSCR and cash flow per door.

What should be in a real estate investor’s buy box?

Two halves. A filter half (market, price range, property type, condition, strategy) and a math half (your good and bad cutoffs for the return and safety metrics). Add a short list of deal killers that are an automatic no.

Is the 1% rule still useful?

As a five-second screen, yes. As a decision, no. It ignores taxes, insurance, financing and repairs. In the worked example above, Deal B passes the 1% rule at 1.23% and still stops short of a Strong Deal, because its all-in cost is 88.29% of its value.

What is a good DSCR for a rental?

BuyBox grades 1.25 and up as good and treats anything under 1.0 as bad by default, because under 1.0 the property cannot cover its own mortgage. Lenders set their own minimums, so check with yours.

How does BuyBox use my buy box?

You set good and bad cutoffs per metric in Settings, then Thresholds. Every analysis is graded against them, and those grades drive the metric colors, the risk flags and a verdict of Strong Deal, Solid Deal, Needs Work or High Risk. A bad DSCR or cash flow per door sends a deal to High Risk on its own.

Can I set different targets for single-family and multifamily?

Yes. Cash flow per door has a separate target for single-family and for duplexes, triplexes and fourplexes, and the verdict uses the one that matches the property type.

How much cash should I leave in a BRRRR?

That depends on your goals, which is why it belongs in your buy box as a hard dollar cap. BuyBox calculates cash left in after the refinance and grades your cash-on-cash and IRR against it, so you see the true return on the money still tied up.

See how BuyBox grades a deal against your buy box. Explore the features or get early access, free.

Appendix: calc engine inputs and outputs

All figures above come from the BuyBox calculation engine, using the default thresholds except where the custom buy box is noted. Property type: single-family. BuyBox starts with holding months, holding costs and growth switched on, so set the zeros below in BuyBox to reproduce these figures.

Base inputs (Deal A): purchase price $210,000; ARV $210,000; buying costs 3%; rehab $0; rent $1,850/mo; funding Conventional, 25% down, 7%, 30 years; property management 8%; vacancy 6%; repairs 5%; capex 5%; insurance $110/mo; tax $230/mo; no refinance; IRR hold 5 years, selling costs 8%; 0 holding months; holding costs $0/mo; no rent growth, appreciation or expense growth.

Deal B: Deal A with purchase price $150,000 and ARV $175,000.

Deal C (BRRRR): Deal A with purchase price $150,000, rehab $30,000, ARV $220,000 (and $200,000), rent $1,800/mo, funding Cash, refinance on, 4 holding months with holding costs $0/mo (the $230/mo property tax still accrues over those months), DSCR refi 25% down at 7% for 30 years, 3% refi closing costs.

Custom buy box (Deal A rerun): cash flow per door SFR good 100 / bad 0; DSCR good 1.10 / bad 1.00; cash-on-cash good 4 / bad 0; all other metrics at defaults.

G = good, W = workable, B = bad. Cash flow per door equals monthly CF for these single-unit runs. Cap rate is on purchase price, the basis BuyBox grades it on. Grades use the default thresholds that ship with BuyBox.