Flip Investor OS
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Formulas, worked examples and checklists for the numbers behind a flip. Written by the Flip Investor OS team; every formula is the one the app runs.
Calculator guides
Maximum offer (70% rule)
The 70% Rule in House Flipping: How to Calculate Your Maximum Offer
The 70% rule: maximum allowable offer = ARV × 70% − repairs. Worked example, when 65% or 75% fits, what the MAO formula ignores, and a full maximum offer.
Read · 9 min readBRRRR
BRRRR Method Math: Cash Left In, Cash Flow and DSCR Explained
BRRRR calculator math: cash invested, refinance at 75% of ARV, cash out, cash left in the deal, NOI, cash flow, DSCR and cash-on-cash on one example house.
Read · 9 min readHard money
Hard Money Loans for House Flips: Points, Interest and Cash at Closing
Hard money loan calculator math for a fix and flip: loan = price × LTC + rehab × LTC, points, monthly interest, total financing cost and cash at closing.
Read · 8 min readHolding costs
Holding Costs on a House Flip: What They Include and How to Calculate Them
House flip holding costs: taxes, insurance, utilities, HOA, loan interest and other bills times the months you own it. Formula, 6-month example, 3 more months.
Read · 8 min readFlip profit
How to Calculate Profit on a House Flip (Formula and Example)
House flip profit = ARV − price − rehab − contingency − closing − financing − holding − selling. Example, cash vs hard money, margin vs ROI, stress tests.
Read · 8 min readARV from comps
How to Calculate ARV (After Repair Value) From Comps
How to calculate ARV: price per square foot of 3–5 sold comps × your square footage. Example, conservative / base / aggressive range, and what a bad comp is.
Read · 9 min readRehab cost by size
How to Estimate Rehab Costs per Square Foot (Light, Medium, Heavy)
Rehab cost per square foot: light, medium and heavy ranges, a 1,600 sq ft example, what moves a house up a level, why a zone-by-zone estimate replaces it.
Read · 8 min readRental quick check
Rental Property Quick Check: 1% Rule, GRM, Cap Rate, Cash-on-Cash and DSCR
The 1% rule, gross rent multiplier, cap rate formula, cash on cash return and DSCR calculation for a rental: what each measures, what it misses, one example.
Read · 8 min readGuides and checklists
Guides and checklists
First House Flip: 10 Mistakes Beginners Make and How to Avoid Them
The ten first house flip mistakes that cost beginners money: ARV from one comp, no contingency, forgotten holding and selling costs, and the fix for each one.
Read · 8 min readGuides and checklists
Flip or BRRRR? How to Compare Both Exits on the Same House
Flip vs BRRRR on one example house: $35,000 profit in six months, or a 75%-of-ARV refinance that leaves $30,600 in the deal and a $1,597 payment to cover.
Read · 9 min readGuides and checklists
How to Walk Through a Flip in 30 Minutes: a 12-Zone Inspection Checklist
A house flip walkthrough checklist in 12 zones: what to photograph and note in each, what a photo cannot tell you, and how the walk becomes a rehab estimate.
Read · 9 min readGuides and checklists
House Flipping Spreadsheet vs Software: What to Track and When to Switch
What a house flipping spreadsheet must track (deal inputs, estimate by zone, original vs forecast vs actual, receipts, bids), where it breaks, when to switch.
Read · 9 min readGuides and checklists
How Much Does It Cost to Flip a House? Every Cost, Line by Line
How much does it cost to flip a house? Purchase, closing, rehab, contingency, financing, holding and selling added up on one example house: $285,000 all-in.
Read · 8 min readGuides and checklists
How to Make an Offer Below Asking on a Fixer-Upper (With the Numbers)
How to make an offer below asking price on a fixer-upper: work back from ARV to a maximum offer with every cost counted, present it, and know when to walk.
Read · 8 min readGuides and checklists
How to Read a Contractor Bid and Compare It With Your Estimate
A contractor bid is comparable only when it names scope, quantities and exclusions. How to read one, spot red flags and compare two bids with your estimate.
Read · 9 min readGuides and checklists
Why House Flips Lose Money: Budget vs Actual and the 7 Usual Causes
Why house flips lose money: seven causes from an optimistic ARV to a forgotten selling cost, with stress tests that show a $35,000 profit shrinking to $4,900.
Read · 9 min read