Rental Property Analysis: What to Check Before You Buy

A rental property analysis is the work you do before you buy: estimate the rent you can collect, subtract the costs you will pay, test the result against bad outcomes, and then ask professionals to check it. You can do the first three steps yourself. The last one matters most, because returns are not guaranteed and this post is not investment, tax or legal advice.

What a rental property analysis is

A rental property analysis turns a house into a set of numbers. You estimate income, list expenses and see what is left. Then you compare that result with your cost to buy and finance the property.

Investors use terms like net operating income and cash flow. Net operating income is rental income minus operating costs, before loan payments. Cash flow is what remains after you also pay the loan. The labels matter less than the habit: use your own numbers, write down every assumption and keep them honest.

The five steps of a rental property analysis

Work through these in order, and write down each assumption as you go.

Step 1: Estimate the income you could realistically collect

Start with rent, but be careful. Use rents you can support from listings and from people who know the local market, not the highest number you can find. If you plan to rent by the room, estimate each room separately, because each room has its own rent and its own vacancy.

Then reduce the number for empty time. A room or a house is not paid every day of the year. The IRS notes in Publication 527 that lost rent for a vacant period is not deductible, so treat vacancy as a real cost, not an accident.

CoRent's host calculator and investor tools can help you compare room-by-room income with a whole-house lease. See room rental income calculator: rooms vs. a whole-house lease for the steps.

Step 2: List every cost, not only the obvious ones

Most weak analyses fail on the cost side. Write down each line, with your own quote or estimate next to it.

• Property taxes and insurance. Ask the locality and an insurance agent.
• Utilities. If you include them, they are your cost.
• Repairs and maintenance. Plan for steady small repairs and an occasional large one.
• Turnover. Cleaning, paint and the empty days between tenants.
• Furnishing. If you rent furnished rooms, this is an upfront and ongoing cost.
• Platform and processing fees. On CoRent, hosts keep 95% of rent with a 5% platform fee on rent collected. See the fees page.
• Professional help. Accounting, legal and inspections.
• Your time. Even if you do the work yourself.

For a deeper look at utilities, furnishing and turnover, read co-living operating costs.

Step 3: Understand how repairs and improvements are treated

The tax treatment of a cost can change your results. In Publication 527, the IRS explains that you must capitalize an expense you pay to improve rental property, while repairs and maintenance may be deductible if they are not capitalized. The IRS also says rental income is generally taxable and that you can generally deduct certain rental expenses, and it points readers to Publication 527 for repairs, improvements and depreciation.

Read IRS Publication 527 and IRS Topic No. 414, then ask a CPA how the rules apply to you. Do not build your plan around a deduction you have not confirmed.

Step 4: Stress-test the result

A plan that only works in a perfect year is not a plan. Rerun the numbers with changes.

1. Add vacancy. What if rooms stay empty longer than you hope?
2. Add repairs. What if the roof, furnace or plumbing needs work in year one?
3. Raise costs. What if utilities and insurance rise?
4. Change financing. What if the loan costs more than you expect?
5. Remove the best month. Would the house still work without it?

If the house still works, your plan has room. If it does not, you have learned that before you bought it, which is the point.

Step 5: Take it to the right professional

A rental property analysis is not finished until someone qualified has looked at it. Different questions belong with different people.

• A CPA or tax advisor: how income, repairs, improvements and depreciation apply to you.
• A lender: what loan fits, and what your payment would be.
• A licensed inspector: the real condition of the house.
• An insurance agent: how your plan is covered.
• The city or county: zoning and occupancy rules, especially if you plan to rent by the room.
• An attorney: leases, entity choices and local law.

CoRent can give you a place to test numbers. It cannot replace any of these people.

How the two models change your analysis

If you compare a single-family lease with renting by the room, the structure of the analysis changes. With a single lease you estimate one rent and one vacancy period. With rooms you estimate several rents and several move-outs. Read rent by the room investing vs. a single-family lease for a side-by-side look at both.

Gather your own estimates and test them in the CoRent investor tools. Returns are not guaranteed, and a careful analysis is your best defense against surprises.

Frequently asked questions

What is the most common mistake in a rental property analysis?

Leaving out costs, especially vacancy, turnover and repairs. Another is using the best-case rent. Write down every line and use realistic numbers.

Can a calculator tell me if a house is a good investment?

A calculator organizes your numbers. It cannot confirm them or guarantee a result. Use it to test your assumptions, then ask professionals to check them.

Who should review my analysis?

At least a CPA, a lender and a licensed inspector, plus your city or county for zoning and occupancy questions if you plan to rent by the room.