Fix & Flip health calculator

Flips fail on hold time and budget variance as often as on a bad purchase. The 70% rule is a screen, not a religion. This calculator stresses max purchase, projected profit, daily hold cost, and how long your cash lasts if the inspector finds a stack.

Who this is for

People with a specific property and numbers — purchase, rehab budget, ARV — not viewers of renovation television. If you do not have comps, your ARV is a wish; the page will still let you type it, and it will still be a wish.

What to enter first

After-repair value, purchase price, rehab budget, and holding costs. Loan amount vs. purchase + rehab is loan-to-cost. Days and daily cost turn a pretty spread into a calendar problem.

Worked example: 3-bed in a B suburb

Original deal sketch.

  • ARV from three sold comps the buyer actually walked: $340,000
  • Contract price: $205,000
  • Rehab bids: $72,000 (not a round $50k “cosmetic”)
  • Closing, carry, utilities, insurance, interest:
  • Planned hold: 120 days
  • Hard-money loan: $220,000
  1. 70% rule max purchase ≈ 0.70 × 340,000 − 72,000 =
  2. All-in cost before sale ≈ 205,000 + 72,000 + (185 × 120) = $299,200.
  3. Projected gross profit vs. ARV before selling costs ≈ 340,000 − 299,200 = $40,800. Selling costs at 7% of ARV ≈ $23,800, leaving ~
  4. Loan-to-cost ≈ 220,000 ÷ (205,000 + 72,000) = 79.4%.
  5. If the job slips 45 days, extra hold = 45 × 185 = $8,325 — half the remaining profit.

The calculator is there to make the delay visible before you pull permits. If profit only works on day 120 exactly, you do not have a margin; you have a schedule.

How to read the results

Max purchase (70% rule) is a filter. Projected profit is the spread after rehab. Daily and cumulative holding cost punish optimism. Capital runway is how many days of surprise you can fund. LTV/LTC show how a lender might see leverage.

Mistakes that make the math useless

  • ARV from asking prices, not closed comps.
  • Rehab budgets that omit dumpsters, insurance, and the second bathroom the inspector will demand.
  • Ignoring selling costs so the “$40k profit” is actually

When to re-run the check

Every time a bid moves, a comp sells, or the lender shortens the term. Do not wait for drywall.

Is the 70% rule required?

No. It is a common wholesale/flip screen. Some markets never pencil at 70%. The page still computes it so you know how far off the screen you are.