The mistake most first-time investors make is treating every listing like a full underwrite — pulling every metric, projecting every scenario, spending 30 minutes per property. The result: analysis paralysis on the first 10 deals, exhaustion by deal 20, no offers written.
Fast rental analysis is a two-pass process. The first pass takes ~2-3 minutes and answers "should I spend more time on this?" using five data points. The second pass — the full underwrite — only happens on deals that survive the first pass. The five data points are: price per unit, rent-to-price ratio, cap rate, cash-on-cash at your loan terms, and DSCR.
The five-metric first pass
1. Price per unit
Divide the list price by the unit count. Compare it against the rough band for the neighborhood and property type. If it's wildly above the band (25%+), the seller is optimistic — pass or offer well below list. If it's wildly below (30%+), there's usually a reason — deferred maintenance, tenant issues, tricky location. Not disqualifying, but worth understanding before committing more time.
Chicago example: a 3-flat in South Shore priced at $140k/door is at market; $200k/door is stretched; $80k/door means the rehab is going to be significant.
2. Rent-to-price ratio (the "1% rule" check)
Monthly gross rent divided by purchase price. The classic "1% rule" says a deal should produce monthly rent equal to 1% of purchase price — a $150,000 property should rent for $1,500/month. Most markets today don't hit 1% cleanly, but the ratio is a fast sanity check:
- Above 1%: almost always cash-flow positive. Rare in appreciation markets; common in cash-flow markets.
- 0.7–1.0%: workable, depends on financing.
- Below 0.7%: hard to make cash flow work at current rates. Depend on appreciation and equity paydown, not monthly income.
3. Cap rate at seller's numbers
Use the seller's NOI (if disclosed) or a quick estimate: gross rent × 0.60 (assuming ~40% expense ratio for a typical small multifamily). Divide by asking price. That's the seller's cap rate.
Compare to the neighborhood band (see What is a good cap rate?). If the cap is way above the band, ask why. If it's at or below, the deal needs financing engineering to work.
4. Cash-on-cash at your loan terms
Estimate: down payment (20-25% of price) + closing costs ($8-12k) + rehab estimate = total cash. Then: gross rent × 0.60 (NOI) − annual debt service (loan payment × 12) = annual cash flow. Cash flow ÷ total cash = cash-on-cash.
Under 5%: probably a pass unless appreciation is the play. 5-8%: workable. Above 8%: strong. Above 12% on paper: check the assumptions carefully; something's likely optimistic.
5. DSCR at your loan terms
NOI ÷ annual debt service. Under 1.20: your lender probably won't approve. 1.20-1.40: workable. Above 1.40: comfortable cushion. See What is DSCR? for the full breakdown.
DSCR is the fastest kill signal — if the deal doesn't qualify with a lender, no other metric matters. Check this early.
The decision tree
After running the five metrics, most deals fall into one of three buckets:
- Pass immediately: DSCR below 1.10, cash-on-cash negative, cap rate wildly off market band. No further analysis. Move on.
- Full underwrite: 3-of-5 metrics pass, and the others are close. This is where you spend the 15-20 minutes to model rehab scope, adjust operating expenses, tune financing, and get a real Deal Score.
- Save for later: All metrics clear but not exciting. Save the property. Come back if better deals dry up or if the seller drops the price.
Why speed matters
Active investors look at 20-50 addresses per week. At 30 minutes of full underwrite per property, that's 10-25 hours per week — a part-time job on screening alone. Most investors can't sustain that pace, so they either burn out or start skipping analysis (which is worse than skipping deals).
The two-pass approach flips the ratio: 2 minutes on 20 properties = 40 minutes total, filters down to maybe 4 deals worth a full underwrite = 60 minutes. Total: 100 minutes per week for the same screening coverage. Sustainable.
What breaks fast analysis
- Trying to be too accurate on the first pass. Fast analysis uses approximations. If you're pulling exact tax records and computing precise CapEx for every listing, you're not doing fast analysis — you're doing slow analysis on more properties.
- Not knowing your neighborhood bands. Fast analysis requires knowing what "market" looks like for your target neighborhood. Cap rate 7%: good in Lincoln Park, terrible in South Shore. If you don't know the band, every property looks average.
- Ignoring the kill signals. If DSCR < 1.10 on the first pass, don't spend 20 more minutes trying to make it work. Move on.
- Not tracking your batting average. Over time, know what percentage of your fast-pass "yes" decisions become actual deals. If it's under 5%, your first-pass criteria are too loose. Above 40%, they're too tight (you're passing on workable deals).
How Prop-Folio makes the first pass one screen
Paste an address into Prop-Folio and the app pulls rent comps, property record, tax data, and market value estimates automatically. Pick a strategy, and the Deal Score across all five metrics lands in about a minute — with the underlying numbers visible if you want to dig in. Sort your saved properties by Deal Score and the shortlist for deeper underwriting is right at the top.
The point isn't to skip careful analysis. The point is to only do it on the deals that survived a fast filter.
Try the first-pass analysis free →
Related: What is a Deal Score? · How to read a Chicago 2-4 unit listing · Cap rate vs cash-on-cash vs DSCR