Worldwide of commercial genuine estate, a building's Net Internal Area (NIA) is important for communicating the functional space, calculating lease rates, and estimating a residential or commercial property's value. This post talks about the nuances of NIA, walks you through the actions in determining it, and describes how modern tools like RoomSketcher can improve this procedure.

What is Net Internal Area (NIA)?

Net Internal Area (NIA) is a measurement used in business genuine estate to figure out the "usable area" within a structure. Usable area suggests the offered areas for tenants' unique or sole use, such as workplaces, retail area, labs, and manufacturing. Areas omitted from an NIA calculation consist of common areas such as shared lobbies, restrooms, or elevators.

NIA is a vital metric for property managers and occupants, as it offers a standardized way to examine the real location available for profession and usage within a building.

Note that meanings of NIA - including which locations count towards it and which do not - vary worldwide. Hence, it's best to inspect with local authorities or an expert appraiser for your area's most utilized measurement standards. Many nations are moving towards International Residential or commercial property Measurement Standards (IPMS), established by more than 80 professionals and non-profit organizations, to document global residential or commercial property measurement requirements.

Practical Tips on How to Measure and Calculate Net Internal Area

NIA is generally the total internal location of a structure minus the interior walls and typical areas. Simply put:

NIA = Gross Internal Area − (Interior Walls + Common Areas)

Here are a couple of ways to calculate NIA:

Option 1: Use an existing plan or layout

If you have an existing plan or floor strategy for the structure, you can import it into layout software like RoomSketcher. With RoomSketcher's integrated area calculator, you can get your NIA lead to seconds - just click to leave out the common areas on the layout and after that select the "Internal Zone Area" calculation (which immediately leaves out the internal walls for you).

See Calculate the Total Area of a Floor Plan to find out more on RoomSketcher's area estimations.

Option 2: Measure onsite

You can also determine up the residential or commercial property if you don't have access to an existing floor plan. If you understand the building's GIA, you can determine the internal walls and common spaces and deduct them. Or, if you don't know the building's GIA, you can add up all the functional area to compute the NIA. For example:

Start with a walkaround - Walk the residential or commercial property to get a concept of the shape and number of floors.
Sketch the external walls on paper or tablet - Make a sketch of the residential or commercial property shape or produce a digital sketch utilizing floor plan software on your tablet.
Note the Usable Space vs the Common Space - Locate the areas or rooms that are usable area and mark these on your sketch. Also, note the typical areas planned to be shared among renters so you do not include them in the computation.
Get the measurements - Now, utilize a measuring tape, roto wheel, or a laser to determine the size of any space or area that counts as functional area. It's helpful to divide the areas into rectangles and determine from the within of all walls. Once you've measured up one side of a rectangle, go ahead and measure the other direction. Remember, don't include any typical areas or shared spaces amongst occupants.
Do the math - Multiply the length and width of each rectangle to determine its size. Combine all the rectangular usable locations on the flooring. Repeat for all floors, and amount the result to determine the building's Net Internal Area (NIA).
What Does Net Internal Area Include?

NIA explains how much "functional area" a structure's interior contains. Examples of locations to include in an NIA measurement are:

Exclusive usage space, such as all spaces or locations planned to be utilized by a single company or occupant, such as reception areas, workplaces, training spaces, labs, workshops, retail area, manufacturing space, storage rooms, staff or break rooms, etc.
Exclusive usage atriums and entryway halls used by one company or renter.
Built-in kitchen cabinetry and storage within exclusive usage locations.
Removable partitions. Include the thickness of non-permanent partitions.
Ramps and other sloping or stepped aspects if they are within the unique usage area.
Ventilation or heating system areas inside an unique use area.

"Because requirements differ slightly worldwide, examine with your regional authorities for a complete list of the basic additions in your location. For instance, expect you use the International Residential or commercial property Measurement Standards (IPMS). In that case, your calculation would include columns and occupant parts of shared walls (also called celebration walls.)"

Net Internal Area Exclusions

NIA computations leave out common locations (also called balance locations) since they are not thought about specific to a particular resident. Examples include:

- Shared entryway halls, lobbies, atriums, and landing areas.
- Shared restrooms, toilets, bathrooms, and janitorial spaces that save products and devices used to preserve typical locations in a structure.
- Lifts or elevators that more than one occupant uses.
- Internal structural walls that separate occupants.
- Any areas controlled by external authorities such as utility business.
- Spaces that are taken up with heating and cooling equipment, and so on, if the devices makes the remainder of the space unusable.
- Any space or location with a ceiling height lower than 1.5 m (5ft).

Top RoomSketcher Tip

"Because requirements differ a little around the world, check with your regional authorities for a complete list of the basic exclusions in your location."

NIA Compared: How It Differs from Other Measurement Standards

Let's take an appearance at the distinctions between Net Internal Area (NIA) and other computations. For extra details on measurement requirements, see GIA Explained, and What is Gross Living Area?

Net Internal Area (NIA) vs. Gross Floor Area (GFA)

The Gross Floor Area (GFA) is typically defined as the overall location of the structure. GFA includes external walls and all locations inside the structure, consisting of entryway lobbies and other common locations, lifts/elevators, stairwells, mechanical equipment locations, corridors, etc. On the other hand, NIA does not include external or internal walls or typical locations.

Net Internal Area (NIA) vs. Gross Internal Area (GIA)

GIA (likewise called Gross Internal Floor Area) includes everything measured from inside the external walls, consisting of internal walls and typical locations in a building. On the other hand, NIA does not consist of the internal walls and common areas.

Net Internal Area (NIA) vs. Gross Living Area (GLA)

Gross Living Area (GLA) is utilized for property rather than commercial residential or commercial properties. As such, the measurements are unrelated. For more information about GLA, see What is Gross Living Area, and How do you Calculate it?

Net Internal Area (NIA) vs. Gross Building Area (GBA)

Net Internal Area describes the amount of functional space within a building and does not consist of external walls, internal walls, or common spaces. On the other hand, Gross Building Area describes the total area of a building and consists of typical locations in addition to internal and external walls.

GBA resembles Gross Floor Area (GFA) in the industrial world.

The Importance of Accurate NIA Calculation

The Net Internal Area is essential for various functions:

Rentable Area: In commercial leases, lease is typically based on the NIA, and tenants are charged based on the usable space they will occupy or utilize, plus a percentage of the typical locations.
Space Planning: For tenants and designers, NIA assists in space planning and developing the layout of workplaces, conference room, and other practical areas.
Comparisons: NIA supplies a standardized metric for comparing different residential or commercial properties. When examining possible areas, occupants and property managers can use NIA to compare the expense and performance of space.
Lease Negotiations: NIA is a key consider lease negotiations. Understanding the NIA permits occupants and property owners to work out lease terms, consisting of rent, maintenance expenses, and other charges based on the functional area.
Building Efficiency: Landlords and residential or commercial property managers use NIA to evaluate the efficiency of a structure's design and to make improvements that take full advantage of the usable space.

Thus, NIA needs to be measured properly and utilizing the agreed-upon requirements in your area.

Frequently Asked Questions About NIA

Does the Net Internal Area (NIA) consist of stairs?

Stairs and ramps are included in the NIA if they are within the special functional space of a single company/tenant. Shared stairs and ramps (used by numerous lessees) are excluded from the NIA measurement.

What is the distinction between Net Internal Area (NIA) vs. Gross Leasable/Rentable Area

Some leases utilize the Gross Lease Area as a basis for rent calculations. A client's Gross Leasable Area frequently includes:

- Their functional area or NIA.

- The area inhabited by any external walls adjacent to their area. For instance, a glass shopfront or a plain wall.

- The space inhabited by their 1/2 of any shared internal walls or party walls.

- A pro-rata share of the common area. For instance, if a renter will inhabit 1/3 of the usable space, their Gross Leasable Area estimation would consist of 1/3 of the typical location space.


If a building is occupied by a single occupant, then the GLA is the very same as the GFA.

What is the distinction between Net Internal Area (NIA) vs. Net Leasable/Lettable Area?

Some leases use the Net Leaseable Area (NLA) as a basis for lease estimations. A customer's Net Leasable Area or Net Leasable Area is usually defined as their functional location (or part of the NIA) inside a structure. Tenants may then pay an additional pro-rata fee for upkeep and using the common space.

Making NIA Measurements Easy and Accurate

In summary, Net Internal Area is an important metric in industrial realty that helps identify the actual usable space within a building. It plays a role in lease arrangements, area preparation, and general effectiveness assessments for both property managers and occupants. It is among several basic measurements used in commercial real estate.

To precisely calculate NIA, you can determine up the functional space in a building or use Floor Plan Software, like RoomSketcher, to enhance the procedure of determining NIA.

Learn what Gross Living Area (GLA) suggests, why it is necessary, and how to properly calculate it for a residential or commercial property. Discover our expert guide.