House flipping guide

How to Estimate Rehab Costs on a House Flip

Written by Alexis Briseno Serrano · Last reviewed August 2026

The rehab estimate is the number most likely to sink a first flip. ARV can be checked against comps and purchase price is written in the contract, but the renovation budget is a forecast, and forecasts drift. The difference between investors who compound and investors who quit is usually a repeatable process for estimating repairs before the offer goes in.

That process is simpler than it looks: walk the property with a category checklist, price each category against typical ranges, classify the overall scope, and carry a contingency for what the walls are hiding. This guide covers each step, with the same category ranges FlipperPro's free estimator uses.

Start with scope: cosmetic, moderate, or full gut

Before pricing line items, classify the project, because scope drives everything downstream: budget, timeline, contractor type, and risk. A useful rule of thumb keyed to a typical single-family flip: totals under $30,000 usually mean a cosmetic project (paint, flooring, fixtures, landscaping); $30,000 to $75,000 is moderate (a kitchen or baths plus one or two systems); above $75,000 you are in full gut territory, where structure, layout, and most systems are in play.

The classification is also a sanity check in reverse. If your line items sum to $28,000 but the house needs a roof, an HVAC replacement, and a kitchen, the total is telling you something is missing from the list, not that the project is cosmetic.

Scope also sets your timeline expectations, and timeline is money once you own the property. A cosmetic project measured in weeks exposes you to one season of the market; a gut renovation measured in months exposes you to two or three. When you classify a project, you are not just budgeting the construction, you are choosing how long your capital and your exit assumptions stay at risk.

Price by category, not by vibe

Whole-house guesses fail because renovation costs are lumpy: a few categories carry most of the budget. Estimating category by category surfaces those lumps. Typical mid-range figures for a single-family flip look like this:

Kitchen: $15k–$50k. The most expensive room in the house per square foot, and the one buyers judge hardest.
Bathrooms: $8k–$25k each, depending on how far behind the finishes are.
Roof: $5k–$20k. Binary in the worst way: it is either fine or it is five figures.
Foundation: $5k–$25k when repairs are needed, and the category most worth a specialist's opinion before you close.
Flooring: $3k–$15k across the house depending on material and area.
HVAC: $3k–$12k for repair versus full replacement.
Windows: $3k–$15k depending on count and quality.
Electrical: $2k–$10k, with panel upgrades and rewires at the top of the range.
Plumbing: $2k–$10k, rising fast when supply lines or sewer laterals join the party.
Paint, interior and exterior: $2k–$8k, the cheapest transformation per dollar in the building.
Landscaping and curb appeal: $1k–$8k, and often the best first impression money can buy.

The walk-through that feeds the estimate

A disciplined walk-through is thirty minutes with a checklist, a camera, and the category list above. Work outside-in: roof, siding, grading, then systems (panel, furnace, water heater, visible plumbing), then room by room for finishes. Photograph everything that looks expensive. The goal is not contractor-grade precision; it is making sure no five-figure category gets discovered after closing.

Age is your shortcut when access is limited. A roof near the end of its service life, a furnace from two decades ago, or original galvanized plumbing each belong in the budget even if they are technically still working on walk-through day.

Reading age and materials like a contractor

You do not need trade licenses to read a house's big signals. A handful of observations, each taking seconds, move real dollars in the estimate:

Roof: curling, missing, or moss-heavy shingles visible from the curb usually mean replacement money, not repair money.
Panel: an old fuse box or a crowded panel hints at electrical work beyond new fixtures.
Water heater and furnace: manufacture dates are printed on the labels, and units deep into their service life belong in the budget even while they still run.
Floors that slope toward a corner, doors that will not latch, and stair-step cracks in brick are foundation questions worth a specialist before closing.
Missing bath fans, missing GFCI outlets, and an empty permit history suggest past work was done informally, which raises the odds of surprises behind the walls.

Carry a contingency, always

Every renovation budget needs a contingency line for what demolition reveals: hidden water damage, surprise knob-and-tube wiring, the subfloor that crumbles under the old vinyl. Seasoned flippers carry roughly 10% to 20% of the renovation budget as contingency, weighting toward the high end on older houses and full gut scopes where unknowns multiply.

Treat the contingency as spent money when you run your deal math. If the project comes in clean and the contingency survives, it lands in profit; if you budget without it, every surprise comes directly out of profit instead.

Turning the estimate into the offer

The rehab estimate's first job happens before you own anything: it feeds your maximum allowable offer. Most investors run it through the 70% rule (keep 70% of ARV, subtract repairs, offer no more than the result) as the screening step, then price the full deal properly once a lead survives the screen. An estimate that is honest at offer time is what keeps the renovation from eating the margin later.

The order of operations matters as much as the numbers: estimate before you offer, never after. An estimate built to justify an accepted price inherits every bias of the negotiation, while an estimate built first disciplines it.

How the estimate gets refined after inspection

The category estimate you build at offer time is version one. The professional inspection is where it grows up: findings either confirm your numbers or reprice them while you still hold an inspection contingency. Inside FlipperPro, each lead carries an inspection checklist with pass and fail grading, and the AI Rehab Analysis reads an uploaded inspection report and returns repair line items prioritized as critical or recommended, so the version-two budget builds itself from the inspector's own findings. The final underwriting pass then shows the original and refined numbers side by side before you commit.

A sample moderate-scope budget

Kitchen refresh: $25,000
One bathroom: $12,000
Flooring throughout: $8,000
Interior and exterior paint: $4,000
HVAC service and repairs: $6,000
Landscaping and curb appeal: $3,000
Subtotal: $58,000
Contingency (about 15%): $8,700
Working budget: $66,700

At $66,700 this lands squarely in moderate scope. The same house needing a roof and a foundation repair could clear $90,000, which is why those two categories get checked before anything else.

Build your own budget in the free rehab cost estimator

Frequently asked questions

Can I estimate rehab costs without a contractor walk-through?

For the screening estimate, yes. A category checklist, typical ranges, and an honest eye get you close enough to make an offer with a contingency behind it. Bring in contractors once the property is under contract with an inspection window: their bids replace your ranges category by category, and the contingency absorbs the difference in the meantime.

Why not just use a price-per-square-foot rehab number?

Because renovation costs are driven by which categories are in scope, not by floor area. Two identical 1,500 sqft houses can differ by tens of thousands of dollars if one needs a roof, a panel, and a kitchen while the other needs paint and carpet. Per-square-foot shortcuts hide exactly the lumpy categories that decide whether the deal works.

Which rehab categories should I check first?

The binary, five-figure ones: roof, foundation, HVAC, and the electrical panel. Each is either fine or expensive, with little in between, so they swing the budget more than any finish decision. Checking them first also protects your offer: a surprise in any of them can move the price by more than your entire negotiating margin.

How do renovation costs change between a cosmetic flip and a gut?

Nonlinearly. A cosmetic project spends on finishes buyers can see: paint, flooring, fixtures, landscaping. A gut adds the systems and structure underneath, and those categories (roof, foundation, electrical, plumbing, HVAC) each carry five-figure ranges. That is why the scope classification matters before line-item math: it tells you which set of categories you are even pricing.

Do holding costs belong in the rehab estimate?

Keep them separate. The rehab estimate prices the physical work; holding costs (loan interest, taxes, insurance, utilities) accrue with time and belong in the deal analysis alongside buying and selling costs. Mixing them into the renovation number makes both harder to track, and makes it impossible to tell whether an overage came from the project or the calendar.

What order should I spend the rehab budget in?

Fix what blocks the sale first: structure, roof, systems, and anything a lender or inspector will flag, because no backsplash rescues a house that cannot pass financing. Then spend where buyers look hardest, kitchens and baths, and finish with the cosmetic layer of paint, flooring, fixtures, and curb appeal. Budgets that run backward, cosmetics first, are the ones that run out before the roof gets fixed.