Fix & Flip ROI Calculator (Cook County)

This walkthrough uses Chicago as an example market — the same math and workflow apply anywhere Prop-Folio operates. See how it works in your market →

Get the calculator

Prop-Folio's Fix & Flip calculator is built into the iOS app. Free for up to 3 saved properties — no card required, no trial countdown.

Download for iOS →

What the Fix & Flip calculator covers

Purchase + acquisition financing: price, closing costs, hard money loan, points, interest reserve
Rehab estimator: 12 categories with quality tiers (basic to premium) and contingency slider
Holding costs: property tax, insurance, utilities, debt service, HOA dues during the hold
Sale + sale costs: ARV, agent commission, transfer taxes, title, closing
Outputs: Projected Profit, ROI, ROI annualized, Maximum Allowable Offer (MAO), Deal Score

The 70% rule and why MAO matters

The flipper's rule of thumb: your offer should be no higher than 70% of ARV minus rehab. So if the rehabbed comps support $310,000 and your scope of work is $58,000, MAO = (310,000 × 0.70) − 58,000 = $159,000. Cook County is generally more forgiving than coastal markets, but profit margins are thinner than they were in 2021–2022.

ATTOM reported the typical flip in 2025 netted $65,981 gross profit at a 25.5% ROI — the lowest ROI since 2008. Underwriting accurately is the only way to stay above water.

Cook County-specific gotchas

City + county transfer taxes

Chicago has a city transfer tax (paid by buyer, 0.75% under $1M) AND a state/county transfer tax. Suburban Cook County only has the state/county tax. The calculator handles this — set the correct jurisdiction.

Cook County reassessment cycle

If you hold for 6+ months you may catch a reassessment that bumps your property tax escrow mid-hold. Plug a higher tax than you'd expect.

Vintage housing surprises

Pre-1940 Cook County stock often hides knob-and-tube electrical, galvanized supply lines, and foundation issues. Use 12–15% contingency, not 8%.

What good Cook County flip numbers look like

Projected Profit: $40,000+ after all costs
ROI: 20%+ on cash invested
ROI annualized: 40%+ (assuming 6-month turnaround)
Deal Score: 70+

If your model is missing any of these, the MAO is too high, the rehab is too aggressive, or the ARV is too optimistic. The calculator shows you which.

How to use it

Download Prop-Folio on iOS and sign up (email only — no card).
Tap the "+" Import tab and paste any Cook County address.
Select Fix & Flip as the analysis type.
Adjust your Purchase, Renovation, Holding, and Sale cards.
Read the Deal Score and metric breakdown.
Export to PDF or save to portfolio.

Get the free Cook County flip calculator →