The clock starts at closing
A flip has three numbers everyone talks about: what you paid, what the rehab cost, and what it sold for. It has a fourth that quietly decides how much of the spread you keep: what it cost to own the house for every month in between. Those are holding costs. They start accruing the day you close on the purchase and stop the day you close on the sale, whether or not a single wall has been touched.
They are easy to skip in a quick analysis because no single line looks large. Added up and multiplied by a timeline that slips, they are. This post itemizes every line, shows how a delay compounds them, and makes the case for putting the total into your offer before you buy rather than finding it on the settlement statement. The fix and flip calculator post covers the full profit stack; this is the one line of it that grows with time.
Every line that accrues while you hold
Some are monthly, some are one-time costs spread across the hold, and each is an input you replace with your own quotes.
Loan interest
If you financed the purchase or the rehab, interest accrues every month you hold. On an interest-only loan it is the loan balance times the annual rate, divided by twelve. Ask which balance the interest is charged on: the full committed amount from day one, or only funds actually drawn. That difference changes the number over a long rehab. The hard money post covers how these loans are structured.
Points and fees, spread over the hold
Origination points, underwriting fees, appraisal and draw inspection fees are paid once, at or near closing. They are not monthly costs, but they are costs of holding: you paid them to have the money for a set number of months. Spread them across your planned hold so each month carries its share, and remember the dollars are fixed. A longer hold does not raise them; it only lowers the per-month figure, which is not a saving. The exception is an extension fee if the project runs past a fixed loan term. That is a cost created entirely by delay, and it belongs in the delay math below.
Property taxes
Taxes accrue daily whether the house is occupied or not. Take the annual bill, divide by twelve, and check whether your purchase triggers a reassessment. Whether you pay the bill during the hold or the taxes are settled between buyer and seller at closing, the taxes for the months you own the house are a real cost of the flip, even if you never wrote a check for them.
Insurance on a vacant property
A policy written for an occupied home may not cover a house that is vacant and under construction, which is why vacant-property or builder's risk coverage is worth pricing for the hold. Treat the product and its cost as a quote you obtain, not a number you assume, and treat the monthly figure as a holding cost. If the policy has a fixed term, note what happens to the premium when the hold runs past it.
Utilities
Crews need power and water, and heat may need to stay on to protect pipes and drying finishes. Electric, water, sewer, gas, and trash stay in your name for the full hold, including the listing period. Budget a monthly figure from the seller's history or the utility's estimate.
Association dues
If the property sits in a homeowners or condo association, dues continue during the hold and unpaid dues surface at your sale closing. Include the monthly amount, and check for any special assessment already approved.
Security, lawn, and upkeep
A vacant house under renovation attracts attention. Lawn care, snow removal, a lockbox or camera, and periodic walkthroughs keep it from looking abandoned. Small lines individually, easy to forget collectively.
Count the whole timeline, not the rehab
The hold is not the construction schedule. It runs from your purchase closing through permitting and contractor lead time, the rehab itself, punch-list and cleaning, listing, days on market, the buyer's inspection and appraisal, and their financing through to funding. A rehab that takes ten weeks can sit inside a hold of five or six months once everything on either side of it is counted. Build the holding estimate on the full span, and build the rehab span from a line-item scope the way the repair cost post lays out, because an underestimated scope is an underestimated timeline.
The worked example
All figures below are illustrative round numbers chosen to make the arithmetic easy to follow. They are inputs, not benchmarks for any market or lender.
- Loan balance assumed: $160,000, interest-only at an assumed 12% annual rate, with an assumed six-month term
- Points and fees assumed: 2 points ($3,200) plus $1,600 in lender fees, $4,800 total, paid at closing
- Planned hold: 6 months from purchase closing to sale closing
Monthly holding costs on those assumptions:
- Loan interest: $160,000 × 12% ÷ 12 = $1,600
- Points and fees spread over 6 months: $4,800 ÷ 6 = $800
- Property taxes: an assumed $3,000 annual bill ÷ 12 = $250
- Vacant-property insurance: an assumed $1,800 six-month premium ÷ 6 = $300
- Utilities: an assumed $200
- Association dues: $0, none on this property
- Lawn, security, and upkeep: an assumed $100
- Monthly holding cost: $3,250
- Six-month holding cost: $3,250 × 6 = $19,500
Nearly twenty thousand dollars, on a deal where each line looked minor, and it assumes everything goes to plan.
What a two-month delay adds
Now the permit takes longer than expected and the house sits on market for six weeks instead of two. The hold runs eight months instead of six. Two things happen to the holding figure, and they are worth separating. First, the recurring lines keep running: interest, taxes, utilities, and upkeep, plus insurance, where the six-month policy has run out and extending coverage is assumed to cost the same $300 a month. The spread-out points are excluded because those dollars were already paid. Second, the loan term is now exceeded, so assume an extension fee of 1% of the loan balance for each month past term.
- Recurring monthly lines (excluding spread-out fees): $1,600 + $250 + $300 + $200 + $0 + $100 = $2,450
- Two extra months of recurring lines: $2,450 × 2 = $4,900
- Extension fee at an assumed 1% per month: $1,600 × 2 = $3,200
- Added by the delay: $4,900 + $3,200 = $8,100
- Eight-month holding cost: $19,500 + $8,100 = $27,600
If the projected profit on this flip was $30,000 after every other cost, the two-month slip takes $8,100 of it, leaving $21,900. Nothing about the house changed. Purchase price, rehab, and sale price were all exactly as planned; the timeline alone moved more than a quarter of the profit. This is how holding costs compound: each month of delay costs the recurring lines, and past the loan term it costs the recurring lines plus a penalty.
A flip does not lose money on the day it sells for less than planned. It loses money one month at a time, on schedule, while nobody is watching the meter.
Put holding costs in the offer, not the post-mortem
Holding costs are a cost of the deal in the same way the rehab is. When you calculate your maximum offer, they come off the top alongside repairs, closing costs, and your required profit; the MAO post shows where they sit in that stack. An offer that leaves them out has priced the house as if you could own it for free, and the market will not refund the difference at resale.
Two habits keep the estimate honest. Price the hold at the full timeline from purchase closing to sale closing, not the construction schedule. Then re-run the deal at that timeline plus two months and ask whether the profit still clears your minimum. If it does not, the offer is too high, and adjusting it now is far cheaper than finding out in month eight.
The short version
List every line that accrues while you own the house: interest, spread-out points and fees, taxes, insurance, utilities, dues, and upkeep. Multiply by the full hold from closing to closing, not the rehab weeks. Add two months and any extension fee, and see what survives. Then put the planned figure into the offer, because the meter starts the day you buy and stops only when someone else owns the house.
