How to Estimate Rehab Costs Before You Buy
6 min read
A practical method for pricing a rehab from a walkthrough — the big-ticket systems, a room-by-room pass, and a contingency that saves deals.
Start with the big, scary systems
Before you count paint gallons, price the items that can sink a deal: roof, foundation, HVAC, electrical panel, plumbing supply lines, and sewer lateral. A single one of these can cost more than a whole cosmetic refresh, and they are the estimates that most often blow up a budget.
On the walkthrough, note the age and condition of each. When you cannot tell, assume it needs work and get a specialist's quote before you close — never after.
Then go room by room
Walk the house in a fixed order — exterior, then each interior room — and assign each space a finish level: cosmetic (paint, fixtures), moderate (some cabinets, flooring, a vanity), or full gut. Kitchens and bathrooms carry the most cost per square foot, so they deserve the most attention.
Ballpark each room against known ranges rather than a single dollar-per-square-foot number, which hides where the money actually goes. Our rehab cost ranges are a good starting reference.
Add contingency — always
Every experienced investor carries a contingency line: commonly 10–20% of the rehab budget, higher on older homes and full guts where you cannot see behind the walls. It is not padding — it is the reserve for the surprises that a walkthrough cannot reveal.
A deal that only works with zero surprises is not a deal. Underwrite so the numbers still hold after the contingency is spent.
Turn the estimate into a real budget
A good estimate is line-item, not a lump sum: categories, quantities, and a price range for each, so you can compare contractor bids against your own numbers and catch missing scope. That is exactly the structure RehabROI turns into a working project budget once you own the property.
Track actuals against that budget as the job runs, and each flip makes your next estimate sharper.
Run your own numbers
Free, no signup — Rehab Budget Estimator.
Ready to track a real deal? Sign in and turn the estimate into a working budget.