The deal landed in your inbox this morning. Three-bedroom 2-bath in Maryvale, list price $310K, says it needs "minor updating." Comparable sales are coming in around $475K for the renovated equivalent. Your gut says it's a deal. Your spreadsheet says maybe. Your hard money lender says you have 24 hours to commit.

Here's how to underwrite it the way an investor who's done 30 of these would.

The math, before anything else

Fix and flip math is brutally simple at the top level: Buy. Renovate. Sell. Profit = ARV − (purchase + rehab + carrying + selling).

What separates investors who keep flipping from investors who do one and quit is the discipline around what numbers go into each line. In Phoenix in 2026, here's what a real underwrite looks like.

ARV (After-Repair Value): Pull three comparable sales of fully renovated homes, sold within the last 90 days, within a 0.5-mile radius. Same bed/bath count, same approximate square footage, same lot type. If you can't find three, expand to 120 days or 0.75 miles — but each variance you accept means more risk in your ARV number.

In our example, three comps in Maryvale of similar 3/2 homes in renovated condition: $465K, $480K, $475K. Median: $475K. Your ARV is $475K — not $500K because you saw one optimistic listing.

Purchase price: $310K accepted.

Rehab budget: This is where new flippers lose money. You don't get to estimate this with eyeballing. Walk the property with a contractor or use a rough Phoenix-market rule:

  • Cosmetic only (paint, flooring, fixtures): $20-35/sf
  • Cosmetic + kitchens/baths: $40-60/sf
  • Full gut: $80-120/sf

For a 1,400 sf home in cosmetic-plus condition, you're looking at $56K-84K. Take the high end. We'll use $80K.

Carrying costs: Loan interest + property tax + insurance + utilities for the projected hold period. With a 6-month flip:

  • Loan interest at 9.99% on $385K = ~$19,200 over 6 months
  • Property tax (Maricopa County) ~ $1,200
  • Insurance ~$700
  • Utilities ~$600
  • Total: ~$21,700

Selling costs: 6% commission ($28,500) + title/escrow ($2,500) + concessions ($3,000-7,000) + capital gains if applicable. Use $35K as a planning number.

The math:

  • ARV: $475,000
  • − Purchase: $310,000
  • − Rehab: $80,000
  • − Carrying: $21,700
  • − Selling: $35,000
  • = Profit: $28,300

That's a $28K profit on a deal that ties up 6 months of your time and around $80-100K of cash (down payment + rehab carry). At those numbers, this is a marginal deal. A flipper with 5 deals in flight will pass and look for the next one.

But if your rehab number is wrong by $20K (often the case for first-timers who didn't get a real contractor bid), you're at $8K profit — basically working for free.

The non-math underwrite

Numbers tell you whether the math could work. The non-math factors tell you whether it actually will.

Days on market for renovated comps. If the renovated 3/2s in Maryvale are sitting 60+ days on market, your hold period assumption of 6 months is fantasy. Use 9 months and re-run. If the math doesn't work at 9 months, pass.

Active inventory of renovated homes in your specific submarket. If 14 renovated 3/2s are listed right now, you'll be competing for buyers — price reductions are likely. Adjust ARV down 3-5%.

Permit complexity. Maricopa County is reasonable for cosmetic work but bureaucratic for additions and major reconfigurations. If the property needs an ADU, a kitchen relocation, or anything structural, add 60 days to your timeline.

HOA. Some Phoenix HOAs require permission for renovations. Read the CCRs before you write the offer. Some restrict short-term rentals if your exit strategy includes keeping the property as an Airbnb instead of selling.

Floodplain. Maryvale specifically has zones with flood risk. Pull the FEMA map. If your property is in a high-risk zone, insurance costs ~3x normal and lenders may require flood certifications that delay closing.

The lender conversation

Once you've underwritten the deal yourself, call your hard money lender — not to ask whether the deal is good (your job, not theirs), but to confirm:

  1. They'll lend on this property type, in this neighborhood, at this LTV/ARV ratio
  2. The rate, points, and fees they're quoting
  3. Whether they can close in your timeline
  4. The draw schedule for rehab funds
  5. Any prepayment penalty or extension fees

At Grand Funding, our standard fix-and-flip program funds up to 90% of ARV, from 9.99%. For our example deal: $475K ARV × 90% = $427K maximum loan. Your purchase + rehab is $390K. So we'd fund the entire deal — you're putting in carrying costs, fees, and maybe a 10% acquisition contribution. That's how experienced flippers run lean.

If your lender can't articulate their underwriting criteria in plain language, you're talking to the wrong lender. Hard money should be transparent about its math.

The walk-through checklist

Before you commit, walk the property and check:

  • Roof: Visible damage, age, sag. Roof replacement is $8-15K and absolutely deal-killing if missed.
  • Foundation: Cracks > 1/4 inch, doors that don't close, sloping floors. Settle damage is expensive.
  • Plumbing main line: Galvanized pipe in pre-1970 Phoenix homes is a $5-10K replacement.
  • Electrical panel: 100A or less in a 1,400+ sf home is a panel upgrade ($2-4K).
  • HVAC age: Replacement is $6-12K. Ask the seller for the maintenance history.
  • Termite damage: Phoenix has termite pressure year-round. Section 1 inspection is $75 well-spent.

Each one of these can blow up your $80K rehab budget. Walk every property — never buy sight unseen unless you've done 50+ deals and trust your contractor's eyes implicitly.

The exit before the entry

This is the rule that took us decades to internalize: don't buy until you know who's buying it from you.

In Phoenix 2026, the typical buyer for a renovated 3/2 in Maryvale at $475K is a first-time buyer using FHA financing or a young couple using conventional with 5-10% down. That tells you:

  1. The property must appraise at $475K — be careful you're not 2-3% optimistic
  2. FHA appraisers will flag any peeling paint, missing handrails, or visible code issues — your renovation must clear FHA standards
  3. Buyers with 5-10% down can't bring much cash — you can't expect price overages
  4. Days on market in this segment: ~30-45 days

If you don't know who's buying it from you, you don't have a flip. You have a property.

The Logan rule

Forty years of building and lending in Arizona has taught us this: deals that need to close in 7 days are usually the deals where the seller knows something is wrong. Take an extra day to underwrite. The deal you don't do is sometimes worth more than the deal you do.

That said: when the deal is right and the math works and you trust your numbers, the speed advantage of a hard money lender is the entire game. You can't underwrite for 4 weeks while a cash buyer takes the deal in 5 days.

Underwrite fast. Underwrite hard. And when the math says go — go.

Want a 24-hour read on your Phoenix fix and flip? Call (602) 935-0371 or apply at grandfundingllc.com/apply. Logan reviews every deal personally.

Related reading: Phoenix Fix & Flip Loans · What is ARV? · What is LTV? · Fix & Flip vs Construction Loans