Free Apartment Size Calculator

Apartment Size Calculator

Calculating the approximate size of an apartment unit can be an extremely helpful tool when the information is not readily available. Understanding the size of an apartment unit is a critical step in understanding its value, layout, and suitability for potential tenants. Try out our apartment size calculator to easily estimate and understand the square footage of an apartment unit.


Calculate Apartment Size

Please input the required fields (*) below to calculate an apartment’s size.

This calculator is meant for educational purposes only. The calculation generated from the calculator does not, and is not intended to, constitute financial advice. As such, all information, content, and materials available on this site are for general informational purposes only. Please review our Editorial Standards for more info.


Apartment Size Calculation Formula

Estimating the size of an apartment can be done with a formula of variable inputs such as bedroom count, bathroom count, etc. Similar to our other rental property calculators, our proprietary formula takes into account all common spaces of an apartment unit and calculates an estimate of square footage for the overall unit, with an included load factor to also account for interior walls.

  • Bedrooms: The number and dimensions of bedrooms contribute significantly to the overall square footage, offering personal space for inhabitants.
  • Bathroom: Bathrooms, varying in size from half-baths to full suites, can significantly affect the total area of an apartment.
  • Living Room: Often one of the larger rooms in an apartment, the living room serves as the central gathering space for residents and guests.
  • Dining Room: This space, designed for meals and gatherings, can range from compact nooks to expansive rooms, influencing the apartment’s total size.
  • Office: Especially relevant in modern apartment layouts, the office space provides a dedicated area for work or study.
  • Extra Room: A versatile space, an extra room can serve as a guest room, hobby room, or any other purpose, adding to the apartment’s footprint.
  • Storage Closet: While generally smaller in dimension, storage closets are essential for housing belongings and utilities, contributing to the overall calculation of apartment size.

Calculating Room Area

Calculating the size of an apartment unit requires understanding how to calculate the area of an individual room. The corresponding image demonstrates how to calculate the interior area of a rectangular room – Length x Width (10′ x15′ = 150′). For rooms with angular or round walls, more advanced calculations can be made to determine the area.

Apartment Size Resources


Apartment Size Calculator FAQ

What’s the Difference Between “Gross” and “Net” Square Footage in Apartment Units?

Also referred to as “Rentable vs Usable”, “Gross” square footage includes the total area of the apartment unit, encompassing wall thicknesses, columns, and other structural elements. “Net” square footage, on the other hand, refers to the usable or livable space within the unit, excluding those structural elements. The net area gives a better idea of the functional space available to the resident.


How to Accurately Measure the Size of an Apartment Unit?

For an accurate measurement, use a tape measure to record the length and width of each room, then multiply these figures to get the area of each room. Sum up the areas of all rooms to determine the total size of the apartment. It’s crucial to consider any alcoves, closets, or irregularly shaped spaces. Digital real estate tools and apps can also help in recording and calculating these measurements.


Are Hallways and Corridors Within an Apartment Included in the Unit’s Total Size Calculation?

Yes, interior hallways and corridors within an individual apartment unit are included in the total size calculation. However, common hallways or corridors outside the unit, which are shared with other tenants in the apartment building, are not.

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