A step-by-step framework for sourcing distressed properties, estimating ARV, calculating renovation budgets, and running your numbers before you make an offer.
The foundation of every successful fix-and-flip is the underwriting — the process of evaluating a deal before you commit capital. Experienced investors spend as much time on the analysis before an offer as they do on the renovation itself. The goal is to know with confidence what the property will be worth after repairs (the ARV), what it will cost to get it there (the renovation budget), and what return that generates relative to the price you're paying. If those numbers don't work on paper, they won't work in the real world.
Estimating ARV starts with pulling comparable sales — properties similar in size, age, condition, and location that have sold in the last 90–180 days. The key word is 'after repair': your comps should be renovated properties in move-in condition, not other distressed properties. Use MLS data when available, and cross-reference with Zillow, Redfin, and county records. Aim for at least 3–5 comps within a half-mile radius and 20% of your target property's square footage. If comps are sparse, expand your radius or time window carefully — the further you deviate, the less reliable the estimate.
Renovation budgets are where most new investors go wrong. The instinct is to estimate low to make the deal work on paper. The reality is that renovation costs almost always come in higher than initially estimated, and a budget miss of 20–30% can turn a profitable flip into a breakeven or loss. Build your budget line by line: demo, framing, roofing, HVAC, plumbing, electrical, insulation, drywall, flooring, cabinetry, countertops, fixtures, exterior, landscaping. Add a 10–15% contingency for surprises — because there will always be surprises. If you're not yet experienced enough to estimate costs yourself, walk the property with a general contractor before you make an offer.
The standard underwriting formula for fix-and-flip is the 70% rule: don't pay more than 70% of ARV minus renovation costs. If the ARV is $350,000 and renovations are $65,000, the maximum purchase price is ($350,000 x 0.70) - $65,000 = $180,000. This formula builds in a cushion for financing costs, holding costs, closing costs, and profit. It's a useful starting point, but adjust it based on your local market and specific deal — in expensive markets where margins are thinner, you may need to be stricter; in lower-cost markets, there may be more room.
Holding costs are frequently underestimated in flip underwriting. Every month you own the property, you're paying interest on the hard money loan, property taxes, insurance, utilities, and potentially HOA fees. On a $250,000 loan at 10.5% interest-only, you're paying roughly $2,187 per month just in interest, plus taxes and insurance. A flip that runs 3 months over schedule can cost an investor $8,000–$12,000 in additional holding costs they didn't budget for. When you build your underwriting model, always estimate the timeline conservatively — add 4–6 weeks to whatever your contractor tells you — and model holding costs as a fixed line item.