Rent has a ceiling and a floor, and they are set by different things. The ceiling is whatever people in that neighborhood will pay for a house like yours. The floor is whatever yours costs to own.
If the floor is above the ceiling, the house is a bad rental at any rent you choose. Finding that out takes about ten minutes.
How do you find the ceiling?
Look at what comparable houses are asking right now, and be strict about comparable: same number of bedrooms, same rough square footage, same school zone, same condition. A renovated three-bedroom two blocks away is not a comp for a dated one.
Two cautions about listing sites. First, an asking rent is not a signed rent. A house listed at $2,600 that sits for two months and rents at $2,400 tells you the market is $2,400. Look for units that have come off the market, not the ones still sitting there. Second, one listing is not a range. Collect five or six and you get a band, which is what you want, because the band is where the decision lives.
Within that band, a few things move the number. A washer and dryer, off-street parking, a fenced yard and whether pets are allowed each shift what a house gets, and so does lease length: a tenant signing for two years is worth a little less rent than one signing for one. None of those move the band by hundreds. If your number sits $300 above every comp, the extras are not the reason.
What does Fair Market Rent tell you?
HUD publishes a figure called Fair Market Rent for every metro area and county, used to set housing voucher payments. It is a useful sanity check and a poor comp.
The reason is in the rule. Fair Market Rents are set at the 40th percentile rent, which the regulation defines as the dollar amount below which the rent for 40 percent of standard quality rental housing units fall within the FMR area, drawn from units occupied by recent movers (24 CFR 888.113). That means most units rent for more than the FMR by design. The same rule also counts utilities other than telephone inside the figure, so a Fair Market Rent for a house where the tenant pays their own power is not comparing like with like.
Use it to check that your number is in the right universe. Do not use it as your asking rent.
What is the floor?
The floor is the rent at which the house pays every bill and leaves you nothing. Take a $265,000 house with 20% down, a 30-year mortgage at 7%, $3,180 a year in property taxes and $1,650 in insurance. Set aside 5% of rent for empty months, 5% for repairs, 5% for big items like a roof, and 8% for a property manager.
| $2,100 rent | $2,354 rent | $2,550 rent | |
|---|---|---|---|
| Rent | $2,100 | $2,354 | $2,550 |
| Empty months (5%) | −$105 | −$118 | −$127 |
| Repairs (5%) | −$105 | −$118 | −$127 |
| Set aside for big repairs (5%) | −$105 | −$117 | −$128 |
| Management (8%) | −$168 | −$188 | −$204 |
| Property taxes | −$265 | −$265 | −$265 |
| Insurance | −$138 | −$138 | −$138 |
| Mortgage | −$1,410 | −$1,410 | −$1,410 |
| Cash flow each month | −$196 | $0 | +$151 |
These are example figures, not a forecast for any market.
The middle column is the floor: $2,354. Below it you pay to own the house. Break-even rent, and the formula behind it works through how that figure is built.
Notice how little the top of the range buys you. Going from $2,354 to $2,550, a $196 increase in rent, adds $151 a month. The other $45 goes straight back out in management and reserves, because both are percentages of the rent.
What does an extra $200 of rent cost in empty weeks?
This is the trade that gets priced wrong. Asking the top of the range is only worth it if the house still rents quickly.
Put the same house at $2,550 and assume it sits empty six and a half weeks a year instead of two and a half, which is 12.5% vacancy rather than 5%. The $151 a month becomes a $41 loss. The extra rent was real and the empty weeks ate it. Four extra empty weeks at $2,550 is roughly $2,350 of rent you never collect, against $2,350 a year gained by charging $196 more, which is why the trade is close to a wash before you count the cost of turning the house over twice as often.
So the number to beat is not the highest rent on the street. It is the highest rent that gets the house filled inside two or three weeks. What vacancy rate to use covers how much that assumption moves the answer.
What will a lender accept?
If you are buying a house that already has a tenant, or refinancing one, the rent you claim gets checked. Fannie Mae requires a Single-Family Comparable Rent Schedule, known as Form 1007, or Form 1025 for a two to four unit property, to validate the monthly gross rents (B3-3.8-02, effective September 2, 2026).
When the appraiser’s market rent and the lease disagree, that same guide tells the lender to provide a written analysis explaining the discrepancy or use the lesser amount. An optimistic rent on your worksheet does not survive contact with an appraiser, so use the band you found, not the top of it.
Putting a number on it
Get the band from comps that actually rented. Get the floor from the calculator. Then pick a rent inside the band that clears the floor with room to spare, and check what happens to it if the house sits an extra month.
If nothing in the band clears the floor, the rent is not the problem. The price, the loan or the tax bill is, and the mistakes that break a rental analysis is the place to look next.