Published 14 September 2026 by Prop-Pocket Team
Get unit, time and economic vacancy formulas, a breakeven occupancy stress test, spreadsheet steps you can copy, and Prop-Pocket automation.
Decorative vacancy rate title card
The unit-based vacancy rate formula is (vacant units ÷ total units) × 100, while the time-based version for a single property is (days vacant ÷ days available) × 100. Both give you a straightforward percentage. A third measure, economic vacancy, tracks lost rental income rather than empty units; it's worth knowing when the first two don't tell the whole story.
TL;DR: - Unit-based vacancy provides a quick percentage of empty units relative to total units, but may overlook unpaid rent or concessions affecting income. - Time-based vacancy calculates the percentage of days a unit remains vacant within a reporting period, offering a more nuanced view of occupancy. - Economic vacancy reveals the financial impact of vacancies by measuring lost rental income, often surpassing physical vacancy figures in misleading situations. - Automating vacancy tracking with software reduces errors from manual calculations and offers real-time insights, especially for larger portfolios.
Vacancy rate expresses the share of available rental capacity, whether that's units or days, that isn't currently earning rent. It sounds simple, and the maths is, but the metric splits into variants depending on what you're trying to learn.
Market vacancy looks at an entire area, a suburb or a city ward, and tells you how tight or slack the local rental market is. Physical vacancy looks at your own portfolio, either as a snapshot count of empty units or as vacant days on a single unit. Economic vacancy goes further still, measuring the gap between what you could theoretically earn and what actually landed in your account.
Which one you reach for depends on your situation. Running several units? A unit-based snapshot works well. Managing just one flat or house? And if you want to know whether unpaid rent, concessions, or bad debt are quietly eating into income that a physical count wouldn't catch, economic vacancy is the more revealing lens.
Here are the three formulas you'll actually use, each with a quick example so you can see the arithmetic land.
Unit-based example: you own a 200-unit block with 10 empty flats. That's (10 ÷ 200) × 100 = a low vacancy rate. Straightforward, and it's the formula most landlords learn first.
Time-based example: a single rental sat empty for several weeks out of a year's time. The vacancy rate, calculated as vacant days divided by total days, results in a moderate vacancy percentage.
Economic vacancy example: your gross potential rent for the year is a certain amount, but due to a void period and a rent concession you offered a tenant, your actual income was lower. Calculating the difference as a percentage of potential rent gives an economic vacancy figure higher than the physical vacancy rates. This number tracks money, not empty rooms, which is why it often surprises landlords who assumed their portfolio was performing better than it was.
Numbers stick better when you walk through them step by step. Here are two calculations built the way you'd actually do them on a spreadsheet or a notepad.
A few notes worth flagging. Pick a consistent reporting period, monthly, quarterly, or annual, and stick with it, because comparing a 30-day figure against a 365-day figure will mislead anyone reading your numbers. Round to one or two decimal places when presenting to lenders or co-investors; more precision than that just adds noise.
Vacancy rate and occupancy rate are two sides of the same coin. Occupancy rate = 100% − vacancy rate, always, because between them they account for every unit or every day. If your vacancy rate is 6%, your occupancy rate is 94%, no separate calculation required.
Benchmarks vary by property type, but rough guides help you sanity-check your own numbers:
Those ranges assume standard residential lets. Student housing often tolerates higher seasonal vacancy around academic-year changeovers without it signalling trouble, and short-let and HMO properties can show much larger swings month to month simply because of how turnover works in those sectors.
Vacancy rate tells you what's empty. Breakeven occupancy tells you how much emptiness you can actually afford before the property starts losing money. The formula is (operating expenses + debt service) ÷ potential gross income, expressed as a percentage.
Worked example: operating expenses plus debt service total a significant amount. Divide that by potential gross income to calculate the breakeven occupancy ratio, which often falls somewhere around three-quarters of full occupancy. If your property runs at a higher occupancy, you have a cushion above breakeven, allowing some room to absorb vacancy without losing money. Lenders and experienced investors use this figure precisely that way, as a stress test rather than a performance score.
Pro Tip: *Calculate your breakeven occupancy once a year alongside your remortgage or renewal planning.
You don't need dedicated software to run these numbers, a basic spreadsheet does the job in seconds.
=(vacant_units/total_units)*100=(days_vacant/days_available)*100=((gross_potential_rent-actual_rent)/gross_potential_rent)*100Paste any of these into Excel or Google Sheets, swap in cell references for your actual figures, and you have a live formula that updates as your numbers change.
For reporting cadence, monthly tracking suits single properties and small portfolios well, while owners managing a dozen or more units often prefer rolling 12-month averages that smooth out short-term noise. Round to one decimal place for internal tracking and keep the raw figures on hand for anything going to a lender.
Illustration of monthly vacancy tracking
Pro Tip: If you're tracking vacancy across several properties by hand, it's easy for one missed tenancy-end date to throw off a whole month's figures. Prop-Pocket landlord software automates this by pulling tenancy dates, rent schedules, and arrears data into one dashboard, so vacancy and economic vacancy figures update automatically rather than relying on a spreadsheet someone forgot to refresh.
Vacancy rate is a useful number, but on its own it's incomplete. A property can show low vacancy and still be underperforming if relet times are creeping up or if you're offering rent concessions to fill gaps quickly, both of which hide inside a headline vacancy figure without showing themselves directly.
I'd argue vacancy only earns its keep as a diagnostic when it's read alongside relet time and concession history, not in isolation. If you manage one or two properties, check vacancy monthly, it's cheap to do and catches problems early. Larger portfolio owners tend to get more signal from rolling 12-month figures, since month-to-month noise from a single tenancy change can otherwise look like a trend. Readers building out a fuller dashboard might find the guidance on monitoring rental profitability a useful next step.
— Harv
Prop-Pocket is the practical alternative to chasing tenancy dates and rent figures across separate spreadsheets. Rather than manually recalculating vacancy every time a tenancy ends, Prop-Pocket landlord software pulls your rent, tenancy, and arrears data into one dashboard and surfaces lost-rent analytics automatically, so you can see both physical and economic vacancy without building the formulas yourself each month.
It suits landlords and small-portfolio managers best, particularly anyone juggling compliance deadlines, repair logs, and rent tracking on top of vacancy monitoring. The platform allows quick onboarding to get your dashboard running efficiently. If you're managing more than one property, or want vacancy figures that update themselves instead of waiting for your next spreadsheet session, take a look at Prop-Pocket's automation features and set up your account.
Divide the number of vacant units by total units and multiply by 100 for a unit-based figure, or divide vacant days by available days and multiply by 100 for a single property tracked over time.
Vacancy rate counts empty units or vacant days, while economic vacancy measures lost rental income as a share of gross potential rent, which can be higher than physical vacancy if you're offering concessions or dealing with unpaid rent.
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