Holding cost calculator

What counts as a holding cost?

A holding cost is anything you pay to simply own the property between settlement and the day the sale money lands. You're not adding value with any of it, which is exactly why it's so easy to leave out of a feasibility. The list is longer than most people expect: loan interest, council rates, water and sewerage access charges, building insurance, standing charges on the electricity and gas even while the place is empty, internet for security cameras during the reno, and land tax if you're holding in your own name above the threshold. On a typical flip, interest is the giant and everything else is the pile of small charges that quietly stacks up alongside it.

Why flippers get the number 30-40% too low

It's rarely one big mistake. It's that holding costs are made of small line items that look trivial on their own and bite hard when they run for months. The single biggest driver is time: every extra week you own the property is another week of interest, rates and insurance against a house that isn't earning a cent. Underestimate the timeline and you automatically underestimate the carry. Three line items in particular get left off almost every spreadsheet I see.

The three costs the spreadsheet forgets

Vacancy utilities. Even with the property empty, the meters keep ticking. Electricity and gas both charge fixed daily supply charges regardless of usage, and if you've put CCTV in during the reno (you should), there's an internet line too. Across a five-month flip that's several hundred dollars most budgets ignore.

The settlement-to-trades window. The holding clock starts the day you settle, not the day the first tradie arrives. Between settling, disbursing finance, booking trades and lodging any council notices, that gap is often three to four weeks of pure carry before a single wall gets touched.

Sale-side carry. Finishing the reno isn't the finish line. Between listing, days on market, and the settlement period after you accept an offer, you're commonly holding another 60 to 120 days after the last tradie leaves — all of it on the same loan. This is the tail that turns a "good flip" into a "broke even".

Land tax: the one that surprises people

If you hold in your own name and your total taxable land value sits above the state threshold, land tax applies — and unlike rates it can be a four-figure surprise. In NSW the general threshold is $1,075,000 of land value, and it was frozen at that level from 1 January 2025 rather than indexed each year, per Revenue NSW. Because the threshold no longer rises with the market, more properties get pulled into the net every year. It's assessed on land value (not the price you paid), it's tier-based, and the structure you buy in changes it, so confirm your position with an accountant before you assume you're under the line.

How to budget it properly

Start with interest, because it dwarfs the rest: multiply your loan by your interest rate, then divide by 12 for the monthly carry. Add council rates ÷ 12 (often $1,800-$3,500 a year in metro Sydney and Melbourne), building insurance ÷ 12 (roughly $1,200-$2,500 a year), water and sewerage access charges, and a flat allowance for vacancy utilities. Then — and this is the step that fixes the 30-40% gap — multiply the monthly total by your full timeline including the settlement-to-trades window and the entire sale period, not just the weeks the trades are on site. The calculator above does this for you; the discipline is being honest about the timeline you feed it.

Why holding costs decide your max offer

Holding costs are one of the four cost buckets that sit inside the buffer the 70% rule carves off to keep a deal safe, alongside purchase costs like stamp duty, the reno and selling costs. Get the carry wrong and you quietly overpay at the auction. It's also one of the numbers the flip ROI calculator folds into the all-in cost, so your return is measured after the real cost of time rather than a headline margin. If you want the full breakdown of the line items and a worked six-month example, the holding costs deep-dive walks through it, and you can see how the carry lands on a real listing in the sample analysis.

This is general information, not financial, tax or legal advice. Interest rates, council rates, insurance premiums and land tax thresholds change and vary by state, lender and site. Figures here are indicative ranges current at the time of writing. Always confirm the current costs and your land tax position for your specific purchase before you commit.