How to calculate rent per square foot for an apartment or a whole building
Divide the monthly rent by the unit's square feet. A 650 square foot unit that rents for $1,040 is $1.60 a square foot. For a whole building, add all the rent and divide by all the square feet: do not average each unit's figure, which gives the wrong answer when the units are different sizes.
One unit: the basic calculation
Rent per square foot = monthly rent divided by square feet. Many listing sites and brokers also quote a yearly number, which is the monthly figure times twelve. Use one convention across all your numbers and say which it is.
Example a made-up unit is 650 square feet and rents for $1,040 a month. $1,040 divided by 650 is $1.60 per square foot a month, or $19.20 a year.
The number is most useful when you compare units in the same building or the same neighborhood. A tiny studio often shows a higher figure per square foot than a large three-bedroom, because kitchens and bathrooms cost the same however small the room is.
A whole building: use the weighted average
To get one number for a building, add up all the monthly rent and divide by all the square feet. This is the weighted average, and larger units count for more, as they should.
| Unit | Square feet | Monthly rent | Rent per sq ft |
|---|---|---|---|
| A | 650 | $1,040 | $1.60 |
| B | 800 | $1,240 | $1.55 |
| C | 950 | $1,425 | $1.50 |
| Building | 2,400 | $3,705 | $1.54 |
Example with made-up numbers. The building figure is $3,705 divided by 2,400, which is $1.544, shown rounded.
The simple average of the three unit figures is $1.55. The weighted average is $1.54, because the biggest unit has the lowest rate. The gap is small here and grows when sizes vary more.
Measure the same way every time
The biggest source of bad comparisons is square footage that was measured two different ways. Some numbers include interior walls and a share of hallways, some only the space inside the unit. County records, the floor plan, and the seller's listing can all disagree.
- Pick one source, such as the lease or your own floor plans, and use it for every unit.
- When you compare with a rental advertised nearby, ask or check how its size was counted.
- Do not count a balcony, garage or basement as living area unless the comparison does the same.
If a size looks wrong, measure it. A wrong size of 50 square feet changes the rate by several cents and can send a price in the wrong direction.
Using it to price a vacant unit
Once you know what similar occupied and advertised units charge per square foot, you can sanity check an asking rent. It is a cross-check, not the only input. Condition, floor, light, parking and amenities matter. How to price a rental listing covers the other inputs.
Example nearby units of the same type rent for about $1.55 a square foot. Your vacant unit is 700 square feet. 700 times $1.55 is $1,085 a month, a reasonable first number to compare against the other signals you have.
The same figure helps with renewals. If one tenant pays $1.35 a square foot and the rest of the building pays $1.55, that unit is below the building's level. Before you raise rent, check your state's limits and notice rules in rent increase notice requirements.
How DoorKeeping handles it
Ask Claude or ChatGPT through DoorKeeping for the rent roll to get each unit's rent in one list. Add the square feet from your leases or floor plans and the assistant can compute the rate for each unit and the weighted average for the building. DoorKeeping does not set or suggest rents on its own. You decide the number, and anything that changes a lease waits for your approval.
Sources
Questions
- How do you calculate rent per square foot?
- Divide the monthly rent by the unit's square feet. Multiply by twelve if you want a yearly figure.
- Is rent per square foot monthly or yearly?
- Both are used. Apartment listings often use monthly. Commercial space is often quoted yearly. State which one you mean.
- Why is a small apartment more expensive per square foot?
- Kitchens and bathrooms cost about the same in a small unit as a large one, so the cost is spread over fewer square feet.
- Should I price every unit at the same rate per square foot?
- No. Use it as a check. Condition, floor, parking and views also change what a unit is worth.