The Five Expenses That Make a Rental Look Better Than It Is

Rental pro-formas are not usually dishonest. They are optimistic in five specific, predictable places, and the same five places every time.

That predictability is useful, because it means auditing one does not require suspicion or expertise. It requires a checklist. Work through the five, put a defensible number on each, and you will have a picture of the property that the seller's spreadsheet did not contain — without disputing a single physical fact about the building.

On the property this article works through, doing that moves the cap rate from 7.57% to 4.42% and annual cash flow from +$3,982 to −$4,348. Nobody lied. Five lines were either absent or priced at the seller's cost rather than yours.

A note before you start. This is general education, not investment advice, and nothing here is a recommendation about any property. The worked example uses illustrative inputs stated on the page — a $265,000 purchase at $2,200 a month, 25% down at 7.125% over 30 years. Property tax figures described as ranges are computed from this site's own sourced 50-state dataset; the specific tax, insurance, and rent on any actual property have to be established for that property. Component lifespans used for the reserve calculation are ordinary planning figures, not measurements of any particular building.

1. The two versions of the same property

Here they are side by side. Left column is how a rental is typically presented; right column is the same building after the five corrections.

An $8,330 gap in NOI, a 3.14-percentage-point gap in cap rate, and the difference between a property that pays you $332 a month and one that costs you $362 a month.

Notice what did not change: the rent, the insurance, the maintenance figure, or anything about the building. Every difference is one of the five below.

2. Vacancy — and why it costs more than the empty months

Typically omitted entirely. A pro-forma showing twelve months of rent is describing a property that never turns over, never sits between tenants, and never has a tenant leave early.

The naive correction is to apply a percentage — 5%, 8%, 10% depending on the market — to gross rent. On our property, 8% is $2,112, and that is the number the audited column uses.

But the percentage understates it, because a vacancy is not just lost rent. A turnover costs:

• Lost rent for the days between tenants
• Make-ready — cleaning, paint, minor repairs, sometimes flooring
• Advertising and screening — listing fees, credit and background checks
• A leasing fee, commonly a half or full month's rent if a manager places the tenant

A single turnover with three weeks of vacancy and a half-month leasing fee costs roughly $1,269 of rent plus $1,100 of leasing fee plus make-ready — call it $3,000 to $3,500 on a $2,200 unit before anything unusual. A property that turns over every two years is absorbing something close to the 8% figure on turnover alone, before counting a single month of genuine market vacancy.

How to size it: ask what tenant tenure looks like in the market and for this property specifically. A property with a five-year tenant has a very different vacancy profile from one that turns annually, and the rent roll and prior leases tell you which you are buying.

3. Management — charge it even if you self-manage

Typically omitted on the reasoning that the owner will manage it themselves.

Charge it anyway, at least once, and look at what it does to the return. The reason is not that you must hire a manager. It is that the analysis has to distinguish between two different things:

• A property that produces a return on your capital
• A property that produces a return on your labour

If the deal only works because you supply the property management free, you have not bought an investment — you have bought a job with an unusual compensation structure. That may be a perfectly good decision. It should be a knowing one, and the way to know is to run the numbers with the fee in and see what survives.

There is a second, more practical reason. Self-management is a decision you can reverse and circumstances can reverse for you. A move, a new job, a health problem, or simply exhaustion turns a self-managed portfolio into a managed one, and a deal that only worked without the fee becomes a deal that does not work at all — at exactly the moment you have least flexibility.

How to size it: 8% to 10% of collected rent is ordinary for single-family, plus a leasing fee on turnover. Charge it on effective gross income, not scheduled rent, because that is how a manager bills — a percentage of what they actually collect.

4. Capital reserves — the expense you have not paid yet

Almost always omitted, because nothing was spent this year.

A roof with twelve years left is not free. It is a roof whose replacement cost you are accruing at roughly a twelfth a year, and the fact that the invoice arrives in year twelve does not make years one through eleven free.

The lazy method is a percentage of rent — 5% is the usual convention, which on our property is $1,320. The honest method is to build it from actual component ages and replacement costs.

That is 11.1% of gross rent, more than double the 5% convention — and the reason is visible in the age column. This is not a new house. The roof is 18 years into a 30-year life, the windows are 22 years into 30, and both are approaching the point where the accrual stops being theoretical.

The audited column uses $2,400 rather than $2,942, which is a deliberately conservative middle position. Either is defensible; zero is not.

How to size it: walk the property with the ages. A home inspection gives you most of them, and the seller usually knows the rest. Multiply each replacement cost by (1 ÷ remaining life) if you want to fund only what is left, or by (1 ÷ total life) if you want a steady long-run accrual. The first is more urgent and the second is more stable.

5. Property tax — the seller's bill is not your bill

Typically shown at the seller's current amount, which in many jurisdictions is a fact about how long the seller has owned the property rather than a fact about the property.

Where a sale triggers reassessment, the tax is recalculated on your purchase price. A seller who bought in 2011 has been paying tax on a 2011 assessed value, possibly with a cap on annual increases, and that number can be far below what you will pay from the first bill after closing.

On our property that is the single largest correction: $2,100 becomes $3,975, a $1,875 annual increase. Capitalised at a 6% cap rate, that one line is worth $31,250 of purchase price.

The variation across states is enormous. This site's sourced dataset puts effective property tax rates from 0.27% to 2.01% of value — a 7.4× spread — with a national average of 0.92% and a median of 0.80%. On a $265,000 property that is the difference between $716 and $5,326 a year, which is more than the entire margin on most deals.

How to size it: find your county assessor's own rules. Some jurisdictions reassess on sale, some reassess on a cycle regardless, and some cap increases for existing owners in ways that reset for a buyer. The assessor's office will tell you, and the answer is worth a phone call because it is one of the two or three largest numbers in the analysis.

6. Maintenance — the difference between a budget and a guess

Usually present but usually low, and distinct from the capital reserve above.

Maintenance is the ongoing stuff: a failed disposal, a leaking tap, a lock change, a service call, gutter clearing, the appliance repair that is not a replacement. Capital reserve is the roof. Both are real; they are different lines and a pro-forma that has one is often missing the other.

The conventions are rough: 1% of property value annually, or 10% of rent, or $1 per square foot. On our property those give $2,650, $2,640, and something near $1,800 respectively — clustering usefully around the $2,400 the audited column uses.

What actually moves it:

• Age. A 1962 house costs more to maintain than a 2016 house, permanently.
• Tenant quality and tenure. Long tenancies generate fewer service calls per year.
• Systems. Well and septic, older electrical, or a boiler add categories of expense a newer house does not have.
• Climate. Freeze-thaw, humidity, and coastal salt all shorten component lives.

How to size it: start from a convention, then adjust for age and systems, then ask the seller for two years of actual repair invoices. If they will not produce them, that is information too.

7. The sixth thing, which is not an expense

Everything above is on the cost side. There is one more line that flatters a pro-forma just as effectively, and it sits at the top.

The rent.

Every figure in this article is built on $2,200 a month, and if that number is wrong, all of them are wrong together — including the corrections. Overstate rent by $150 and you have overstated effective gross income by $1,656 after vacancy, which is more than the entire capital reserve correction.

Three ways a rent figure gets overstated, in rough order of frequency:

The rent roll is aspirational. A rent roll is a document the seller typed. It states what the leases say, or what the seller believes the units could achieve, and it is not evidence of anything on its own. The three things that convert it into evidence are twelve months of bank deposits, the actual signed leases with every addendum, and a tenant estoppel certificate signed by the tenant rather than by the seller.

The current rent is above market. A tenant who has been there six years at a rent that has drifted up with the lease is not evidence that a new tenant will pay it. If the unit turns over, you re-let at market, and market may be below what the rent roll shows.

The current rent is below market and the pro-forma uses "market." The mirror image, and the more seductive one, because the upside is real. But capturing it requires the tenant to leave, the unit to be brought to market condition, and the market to still be there when you re-let. That is a plan with three dependencies, not a line in this year's income.

How to establish it: find genuinely comparable units — same bedroom count, similar condition, same submarket, currently listed or recently let — and read what they are actually asking. Then discount for anything your property lacks. This is the one input in the whole analysis that no dataset can give you, on this site or anywhere else, because rent is set unit by unit and no honest national source exists at the property level. It is legwork, and it is the highest-leverage legwork in the process.

The general rule: treat rent with at least as much suspicion as expenses. The five omissions above are errors of subtraction and this is an error of addition, and an error of addition at the top of the sheet propagates through every line beneath it.

8. What the audit is actually for

It is worth being clear that the point of all this is not to talk yourself out of buying.

The five corrections do not make a good deal bad. They tell you which one you are looking at, and they do it before you are committed rather than after. Three specific things they enable:

They set your maximum price. If the audited NOI is $11,720 and you need a 6% cap rate, the property is worth $195,333 to you rather than $265,000. That is a number you can negotiate from, and it is grounded in arithmetic rather than in how much you want the deal.

They tell you what would have to change. Rent $300 higher, or a purchase price $40,000 lower, or self-management for the first three years — each is a specific lever, and the audit tells you how far each would have to move.

They stop you buying the seller's holding period. Almost every optimistic pro-forma is describing what the property did for someone else, under their tax basis, their financing, their management arrangement, and their tolerance for deferred maintenance. You are not buying that. You are buying the building.

The corollary is worth stating too: a deal that survives all five corrections is a genuinely different proposition from one that only works on the presented numbers, and it is worth moving quickly on. The audit is as useful for building conviction as for avoiding mistakes.

Frequently asked questions

Is 8% the right vacancy rate? It depends entirely on the market and the property, and the honest answer is that you should derive it rather than adopt it. Consider turnover frequency, typical days on market for comparable rentals, and the leasing and make-ready cost of each turnover — which together often exceed a naive percentage of rent.

Do I really have to charge a management fee if I manage it myself? Not on your tax return — that is a real expense only if you actually pay it. But you should charge it in the analysis, because otherwise you cannot tell whether the property produces a return on your capital or only on your labour. And self-management is reversible in ways you may not choose.

Where does the capital reserve go if I never spend it? Into an account, ideally a separate one. It is not a paper entry — it is a fund for a cost that is certainly coming. Treating it as theoretical is how a $14,000 roof becomes an emergency rather than a scheduled expense.

How do I find out what the property tax will be after I buy? Ask the county assessor directly. The rules differ by jurisdiction — some reassess on sale, some on a cycle, some cap increases for existing owners in ways that reset for a buyer. It is one of the largest lines in the analysis and it is knowable before you make an offer.

Isn't a 51.7% expense ratio very high? It is at the upper end of ordinary for a single-family rental with third-party management and an honest reserve, and it is a long way from unusual. The number to be suspicious of is a low one — under about 35% almost always means a line is missing.

The seller says they never have vacancies. Should I believe them? Possibly, and it still does not change the analysis. Their tenure history is evidence about the property, but you are underwriting a decade of ownership that includes turnovers you cannot predict. Ask for the leases and the bank deposits; the rent roll on its own is a document the seller typed.

Does this apply to a property I already own? Yes, and it is worth doing. The same five lines determine whether a property you hold is actually performing, and the reserve question in particular is easier to answer honestly about a building you know than about one you are touring.

What if the audited numbers still work? Then you have a considerably better deal than most, and you now know why rather than hoping. Move on it.

What to do next

The point of the audit is a number you can act on. The rental analysis calculator builds NOI in the order this article describes — gross rent through vacancy to effective gross income, management charged on collected rent, the mortgage kept out of NOI — and includes a sanity panel that flags exactly the omissions that flatter a deal.

• Investment cash-to-close — what getting in costs, including the reserves nobody puts on an estimate
• Hold-period return calculator — what the audited deal returns over a full hold, including paydown
• Cap rate, cash-on-cash, and DSCR explained — what each metric built on this NOI actually measures
• How our figures are sourced

This article is general education about rental property analysis, not investment, tax, or financial advice, and nothing here is a recommendation about any property. The worked example uses illustrative inputs stated on the page; every derived figure is arithmetic on those inputs. Component lifespans and expense conventions are ordinary planning figures rather than measurements of any building. Property tax ranges are computed from this site's own sourced 50-state dataset. Verify every figure for the specific property with the county assessor, an inspector, and the seller's actual records before making an offer.