Calculator
Real Estate Flip Profit Calculator
Real Estate Flip Profit Calculator
Agent + closing + staging + repairs before sale
The 70% rule says a flipper should pay no more than 70% of the after-repair value minus renovation costs. Use this calculator to test whether your numbers clear that bar before making an offer. The "Selling Cost %" slider captures agent commissions (5-6%), transfer taxes, and any pre-sale touch-ups.
Net Flip Profit
$21,450
ROI
5.7%
Annualized
11.5%
The flip nets $21,450 on $403,550 total — a modest 5.7% ROI (11.5% annualized). Thin margins mean any overrun in reno or selling costs pushes the deal negative. You earn about $3,575 per month of holding time. Consider negotiating buying costs or adding value to the property to widen the spread.
*Excludes federal/state taxes and assumes costs as entered; actual projects often overrun budget. Educational only, not investment advice.
The Math Behind Every Successful Flip
A house flip is a simple trade in principle — buy below value, add value through renovation, sell above cost — and an unforgiving trade in practice, because the profit lives entirely in the gap between a handful of estimates. Every input is a guess: what the property is worth after repairs, what the repairs will actually cost, how long the hold will really take, and what the market will pay on the day it sells. The margin between those guesses is the business, and the most common failure mode is not bad luck but arithmetic done loosely at the start, then discovered precisely at the end. For US investors the discipline has a name: the 70% rule, which says a flipper should pay no more than 70% of after-repair value minus renovation costs. This calculator operationalizes the full economics behind that heuristic: purchase price, renovation budget, financing and loan costs, the monthly carry costs during the hold, the total selling costs, and the target sale price. It prints the net profit, the return on total invested capital, the annualized return that makes flips comparable across hold periods, and the profit per holding month — the number that reveals whether a deal is earning its time. The same arithmetic runs forward and backward: enter the numbers honestly before the offer, or run them after the renovation blows the budget, and the tool tells the same truth either way. The goal of any flip analysis is to meet the truth on paper before meeting it in the bank account.
Every Cost Counts Twice: Once Now, Once at Sale
The total cost of a flip is the sum of everything spent to acquire, renovate, carry, and sell: purchase price plus renovation budget plus financing costs plus months times monthly carry plus selling costs as a percentage of the sale price. Profit is simply the sale price minus that total, and the arithmetic is unforgiving because every cost item is inescapable — a cost forgotten in the analysis does not disappear when the deal closes; it arrives at the settlement statement. The monthly carry deserves emphasis: interest on the borrowed money, taxes, insurance, and maintenance running every month of the hold, and a hold that stretches from six months to nine quietly adds three months of that burn to the cost basis. The deals that lose money most often lose it here — not in the purchase or the sale, but in the months the project took longer than planned. The two return figures answer different questions. ROI on total cost divides profit by all money that went into the deal, giving the return on the full capital deployment; annualized ROI converts that to a yearly rate by multiplying by twelve over the hold months, which is the only honest way to compare a six-month flip against a three-month one, since a 20% gain over three months is a very different business than a 20% gain over twelve. The third reading — profit per month of hold — is the one that catches bad deal structure: a flip that earns $18,000 over nine months is producing $2,000 a month, roughly what a part-time job pays, and the question that number raises is whether the capital and the risk are working hard enough. A flip that earns the same dollars in four months is a different kind of investment entirely, and the annualized figure exposes the difference the absolute profit number hides.
Expert Insights
Run the Numbers Three Times Before the Offer
Professional flippers price a deal with three sets of assumptions: the plan case, the likely case with renovation costs inflated fifteen to twenty percent and the sale price pulled down five percent, and the bad case with both moved against them. The offer price should clear a reasonable return in the likely case, because the plan case is the marketing and the bad case is the tail risk. The calculator makes this discipline mechanical: run the inputs three times, and any deal that only pencils on the optimistic numbers is a gamble priced as an investment. The margin between the three outputs is the actual risk of the deal, and it is visible on paper before the inspection appointment is made.
The Selling Costs Are the Silent Margin Killer
A flipper who thinks in terms of gross spread — sale price minus purchase price minus renovation — systematically overestimates every deal, because the settlement side of a sale carries its own bill: agent commissions of five to six percent, transfer taxes, pre-sale touch-up, staging, and closing fees that together commonly consume seven to nine percent of the sale price. On a $425,000 sale, that is a $30,000 line item that never appeared in the purchase analysis. The selling-cost percentage in this tool exists so that number is entered deliberately rather than discovered at closing, and the honest way to set it is from a specific quote for that property's market, not from a round number picked because the deal needed the margin.
Annualized Return Is the Honest Scoreboard
The absolute profit number flatters slow deals and punishes fast ones: $21,000 over six months reads as a good flip, but annualized it is 8.5% — less than an index fund returned with none of the risk. $12,000 over three months reads as a thin flip, but annualized it is around 50%. Capital that completes three turns a year at modest per-deal returns outperforms capital that completes one turn a year with a larger check, because capital velocity compounds. The annualized ROI the calculator prints is the number that should govern the go/no-go decision, and the profit-per-month figure is the discipline that stops a deal from quietly becoming a two-year project that returns what a bank account pays.
Actionable Tips
- 1
Back Into Your Maximum Offer Price
Set a minimum acceptable annualized return, hold the renovation and carrying estimates at realistic values, and let the calculator find the highest purchase price that still clears the return. That number is the offer ceiling — enter bids starting from it, not from what the seller asks. Most first-time flippers do the reverse: they start from the asking price and hope the sale covers the costs. The discipline of a fixed return floor converts every negotiation into arithmetic, and a deal that only works above the floor is a deal to walk away from.
- 2
Budget the Renovation With Contractor Quotes, Not Percentages
A renovation estimate expressed as a percentage of the purchase price is a guess wearing a number's clothes; a renovation budget built from itemized contractor quotes is arithmetic. Get at least two written quotes before finalizing the analysis, and add fifteen percent for the overruns every experienced flipper reports. The calculator's sensitivity to the renovation input is the reason: a $10,000 overrun on a $310,000 flip is three percentage points of return, which can be the entire difference between a deal that works and one that fails. The input deserves the accuracy it will demand when it is real money.
- 3
Treat the Hold Period as a Budget, Not an Estimate
Set the holding period from the renovation timeline plus a realistic listing and closing window, then add a month of buffer before entering the number. Every additional month of hold adds the monthly carrying cost to total cost and divides into the annualized return simultaneously — a double charge that compounds the overrun. The profit-per-month readout makes the trade-off visible: if the deal needs nine months to clear a reasonable return, the renovation scope may be too large for the spread, and a smaller project with a faster cycle is often the better allocation of the same capital.
Real-World Examples
Jordan Walked Away From the Spread
Jordan walked a property listed at $330,000 with a projected after-repair value of $425,000 and a $40,000 renovation scope. The gross spread looked like $55,000, but the calculator's full cost stack — carry, financing, and seven percent selling costs — showed the net at under $8,000 over a six-month hold, an annualized return below a savings account. He made an offer at $305,000 that reflected the math, was refused, and walked away. Four months later the property sold to another buyer at $418,000 with a reported renovation overrun; the deal's thin margin had told the truth about its risk before the market confirmed it.
Priya Found Her True Cost of a Slow Reno
Priya's six-month plan stretched to nine when the contractor found foundation issues. The carry cost she had budgeted at $1,800 a month quietly added $5,400 over the extra time, and the calculator's profit-per-month readout — falling as the hold stretched — showed the deal's annualized return sliding from 17% toward 11%. Seeing the arithmetic mid-project changed her decisions: she compressed the remaining finish schedule, paid a premium to accelerate the plumbing final that she had planned to sequence, and listed two weeks early. The trade-off — a $2,200 premium against $3,600 of saved carry and the recovered return — was the arithmetic the calculator made visible while there was still time to spend it.
Tom's Duplex Lesson in Velocity
Tom had tied up capital for eleven months in a single-family flip returning 14% annualized, and passed on two smaller duplex flips that each returned 22% annualized over four months because the bigger profit per deal felt more substantial. The math said the opposite: two duplex turns at 22% over the same year outproduced the single long hold by a wide margin, and the capital spent eleven months doing one job instead of three. From that point on he priced every deal by annualized return and hold months, and the flip that looked thin on the page became the better allocation every time. The scoreboard is velocity, not check size.
Glossary of Terms
- After-Repair Value (ARV)
- The property's estimated market value after renovation is complete — the anchor number behind the 70% rule and every flip margin calculation.
- Carrying Costs
- Interest, taxes, insurance, and maintenance paid each month of ownership during the renovation and sale period — the cost of time.
- 70% Rule
- The flipper's heuristic that a purchase offer should not exceed 70% of after-repair value minus renovation costs.
Frequently Asked Questions
Everything you need to know about this topic.
Ivy Sinclair-Wren
Financial Chaos Analyst
Ivy Sinclair-Wren is a Financial Chaos Analyst covering investing, AI, wealth psychology, and the emotional consequences of opening finance apps during market crashes. Based in Melbourne, she specializes in demystifying the US tax code and helping users navigate the intersection of spreadsheet logic and human irrationality.