How to Estimate Rehab Costs for a Flip

The repair budget is the input most likely to sink a flip — and the one most often guessed. Both the 70% rule and your flip profit lean directly on it, so a repair estimate that's off by $20,000 is a maximum-offer error of $20,000 and a profit error of the same. The fix is to stop estimating and start itemizing.

Build from a scope of work, not a rule of thumb

“$30 a square foot” is fine for the very first glance and useless for an actual offer. Two 1,500 sq ft houses can differ by $60,000 depending on whether the roof, systems, and kitchen need replacing. A real budget is a line-item takeoff: walk the property, list every category of work, and price each one.

The categories to price

A reasonably complete rehab breaks into these buckets:

• Exterior — roof, siding, gutters, windows, exterior paint, landscaping
• Major systems — HVAC, electrical panel and wiring, plumbing, water heater
• Kitchen — cabinets, countertops, appliances, sink and fixtures
• Bathrooms — tub/shower, vanity, toilet, tile, fixtures
• Interior — flooring, drywall, interior paint, doors, trim, lighting
• Structural / foundation — the expensive surprises; inspect for these before you commit
• Permits, dumpsters, and cleanup — small line items that add up

A worked example

Always add contingency

No renovation goes exactly to plan. Behind every wall is a chance of rot, outdated wiring, or a code issue that wasn't visible on the walkthrough. Add a contingency of 10–20% on top of your itemized subtotal — closer to 20% on older homes or gut rehabs, closer to 10% on light cosmetic work.

The contingency is the difference between an estimate and a budget. Skipping it is the single most common reason a flip that “pencilled out” loses money.

A few honest cautions

• Get real quotes for big-ticket items. Roof, foundation, and full system replacements should be priced by a contractor, not guessed. These are where the largest errors live.
• Match the finish to the ARV. Spending for a luxury kitchen in a mid-market neighborhood doesn't raise your ARV — the comps cap it. Budget to the neighborhood.
• Don't forget holding costs. The rehab budget covers the work, not the months of taxes, insurance, and loan interest while it's underway — those belong in your full deal analysis.