Quick Screen Calculator — The 1% and 50% Rules for Fast Deal Filtering

Before a full model, screen deals in seconds. The 1% rule checks price-vs-rent; the 50% rule checks expenses. This guide shows how to use both without fooling yourself.

A quick screen calculator protects your most scarce resource: time. With hundreds of listings, you need a 30-second filter before building a full pro forma. The two classic screeners are the 1% rule and the 50% rule.

The 1% Rule

The 1% rule states monthly rent should be at least 1% of purchase price. It is a price-to-rent sanity check:

Pass if Monthly Rent ≥ 0.01 × Purchase Price

In high-cost markets (CA, NY, MA) 1% is rare; many investors now use 0.8% as a floor. In the Midwest and South, 1%+ is still common.

The 50% Rule

The 50% rule estimates operating expenses (excluding the mortgage) at about half of gross rent. If rent is $2,000, expect ~$1,000 in operating costs. It is a screening shortcut, not a measurement — well-run new builds may hit 40%, older homes 55%.

Combining the Rules

Use 1% to reject overpriced markets fast, then 50% to confirm expenses are plausible. A deal that passes both earns a full model. One that fails both is a pass.

The Reverse 1% (Max Price)

You can invert the rule to find the most you should pay: Max Price ≈ Monthly Rent ÷ 0.01. At $2,150 rent, that is $215,000. Pay more and you break the 1% screen. This pairs with our max offer calculator.

When the Rules Mislead

1. High appreciation markets: coastal deals fail 1% but may still win on equity growth.
2. Value-add: a failed 1% today may pass after a rehab raises rent.
3. Short-term rentals: STR income dwarfs long-term, so 1% understates potential (use the Airbnb calculator).
4. Owner-occ: house-hacking (live in one unit) changes the math entirely.

Screening Workflow

• Step 1: Pull rent comps for the address.
• Step 2: Apply 1% — does rent clear 1% of ask?
• Step 3: Apply 50% — do expenses look ≤ half rent?
• Step 4: If both pass, build the full cash-flow model.

Where Your Rent Number Comes From Matters Most

A screen is only as good as the rent figure you feed it, and rent estimates vary wildly by source. Rank your inputs by reliability: (1) actual signed leases on comparable units in the same submarket — ask the listing agent for the current rent roll on tenant-occupied properties; (2) active listings on Zillow/Apartments.com filtered to the same bed/bath count within a half-mile — note these are asking rents, so shade them down 3–5%; (3) automated estimates (Rentometer, Zestimate-style rent tools), which are fine for a first pass but routinely miss by 10%+ on unusual layouts, basements, or transitional blocks. If two sources disagree by more than 10%, screen with the lower number. The most expensive screening mistake is not a bad formula — it is running a correct formula on an optimistic rent.

The Third Screen for a 7% World: Quick DSCR

The 1% and 50% rules were popularized in a 4% mortgage era. At today's higher rates, a deal can pass both and still bleed cash after debt service, so add a 30-second third screen: quick DSCR. Take half the monthly rent (your 50%-rule NOI), then divide by the estimated principal & interest on an 80% LTV loan. As a mental shortcut, monthly P&I is roughly $7 per $1,000 borrowed at ~7.5% on a 30-year note. Example: $200,000 price, $2,000 rent → NOI ≈ $1,000/month; loan $160,000 → P&I ≈ $1,120. DSCR ≈ 0.89 — below 1.0, meaning negative leverage despite a clean 1% pass. Anything under ~1.10 on this quick check should either die at the screen or move on only with a rate-buydown or larger down payment thesis. Run the survivors through the loan comparison calculator for the exact payment.

Screening Discipline: Run a Funnel, Not a Wish List

Screening works when it is a numbers funnel with honest kill rates. A realistic shape in a competitive market: 100 listings reviewed → 15 pass the 1% (or 0.8%) screen → 8 survive the 50% expense sniff test → 4 clear quick DSCR → 2 get a full model → 1 gets an offer. If everything you screen seems to pass, your rent inputs are optimistic or your threshold is too loose for your market tier; if nothing passes for months, your market may simply not cash-flow at current prices — a finding worth acting on (switch submarkets or strategies) rather than overriding. Save every passing candidate to saved deals so the funnel's history keeps you calibrated.

Using the Calculator Below

Enter price, rent, and estimated expenses. The tool returns the 1% pass/fail, the 50% estimate, and a quick cash-flow hint. Use it on listings during your search — load the sample to see a passing deal.

Disclaimer: Screeners are approximations. Always confirm with a detailed model and local data before buying.

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