How to Estimate Rehab Costs on Your First Flip (Before You Own the House)
Your rehab estimate is the number most likely to blow up your deal — and you have to guess it before you even own the house, standing in someone else's living room for 30 minutes. Here's how to get close enough to make a safe offer.
Why this is hard (and why it matters so much)
In deal analysis, rehab is one of only two big variables you control the estimate on (ARV is the other). Underestimate it and the profit you counted on disappears. The good news: you don't need a contractor's precision to make a safe offer — you need a disciplined, slightly pessimistic estimate and a buffer.
The three-tier shortcut for a first pass
Before you price a single item, categorize the whole house. Experienced flippers ballpark rehab by level of work and square footage:
| Rehab level | Rough cost / sq ft | What it means |
|---|---|---|
| Cosmetic (light) | $15–$25 | Paint, flooring, fixtures, minor kitchen/bath updates. Systems are sound. |
| Moderate | $25–$45 | Full kitchen & baths, some systems, roof or HVAC, cosmetic throughout. |
| Heavy / full gut | $45–$75+ | New systems (electrical, plumbing, HVAC), structural, layout changes, everything. |
A 1,500 sq ft house needing a moderate rehab is roughly 1,500 × $35 = $52,500 as a first-pass number. Costs vary a lot by region and finish level, so treat these as a starting bracket, then refine.
Build a line-item estimate
Once a deal survives the first pass, walk the house with a checklist and price the big buckets. The categories that make up almost every rehab:
- Roof — age and condition; a full replacement is often $8,000–$15,000+
- HVAC — furnace/AC replacement commonly $5,000–$10,000
- Electrical & plumbing — updates or full re-do; the scariest surprises hide here
- Kitchen — cabinets, counters, appliances; the single highest-ROI room
- Bathrooms — per bathroom budgets add up fast
- Flooring & paint — priced per sq ft, whole-house
- Windows, exterior, landscaping — curb appeal that drives ARV
- Permits & dumpsters — small line items beginners forget entirely
The three mistakes that wreck first-timers' budgets
1. No contingency buffer
Always add 10–20% on top of your estimate for the surprises you can't see through drywall — old wiring, water damage, code issues. If you don't use it, great; that's extra profit. If you do (you will), you're covered.
2. Forgetting holding costs during the rehab
Rehab isn't just materials and labor — every month the project runs, you're paying loan interest, taxes, insurance, and utilities. A rehab that takes 5 months instead of 3 can quietly cost thousands more. Budget realistic timelines, then add a month.
3. Getting one bid instead of three
Contractor prices vary wildly. Get at least three written bids on any significant scope, and be wary of the lowest one — it often means something was left out. A reliable contractor who finishes on time is worth more than the cheapest quote.
Tools and help
Beginners often use a rehab-estimator spreadsheet (ours, below, includes a rehab worksheet), and some investors use apps that generate scope-of-work estimates. When you're evaluating a lot of properties, this is also where a good local contractor relationship pays for itself — walk your first few deals with someone experienced if you can.
The bottom line
Estimate rehab in two passes: a fast per-square-foot bracket to screen the deal, then a line-item walk-through with a 10–20% buffer before you commit. Pessimism here is a feature, not a bug — the flip that survives a conservative rehab estimate is the flip that actually pays.