The difference between gross and net area – what does it mean for you as a tenant?

When companies are looking to rent office space, they are often presented with an offer based on the size of the office in square meters (m²). This seems logical – you pay based on the size of the space. However, there can be a significant difference in the actual usable space between two offices that both list the same size, for example 500 m².

The reason is that the stated size, which the offer is based on, often includes a markup for shared/common areas in the building. This is referred to as the gross leasable area (BTA). Commercial buildings vary greatly in how much is defined as shared space – everything from hallways, staircases, elevators, entrances, canteens, conference centers to fitness facilities.

The space you actually have for your company’s exclusive use is called the net area (NTA). This is the interior space available for your own workstations, meeting rooms, and internal functions.

What do the standards say?

In Norway, the standard NS 3940:2012 – Area and volume calculation of buildings defines the different types of areas:

• Gross area (BTA): The total area of the building measured to the outer edge of external walls or to the middle of walls shared with other units or common areas.

• Usable area (BRA): Net area plus the space taken up by internal walls, shafts, etc.

• Net area (NTA): The actual interior space available exclusively for the tenant.

This means that two office spaces with the same gross area (BTA) can have very different net areas available.

How big can the difference be?

In practice, the gross area can be 10–30% larger than the net area, sometimes more. An office of 500 m² BTA might therefore only provide 350 to 450 m² of net area, depending on the building’s layout and amount of shared facilities.

This is also why many tenants are surprised when they view a space – “this feels much bigger than expected” or “this feels much smaller than the brochure suggested.”

What does this mean for you as a tenant?

As a tenant, this means you must consider how much you are willing to pay for shared spaces, and what value they bring to your business.

Examples:

• Canteens and social areas: If you value a shared canteen that contributes to employee wellbeing and efficiency, it may be worth paying for this via the gross area calculation.

• In-house solutions: If you prefer having internal break areas or eating spaces, you will need to allocate that within your own net area – requiring more exclusive space.

• Efficiency: For consultancy firms where employees often work off-site, it might not make sense to pay for large common areas. A more compact and efficient net area could be more cost-effective.

What do shared areas cost?

Figures from RSM Norway (2023) show that shared operating costs in office buildings typically range between approx. 230–570 NOK per m² per year for properties with high operating costs. This comes on top of the base rent, showing that shared spaces can represent a noticeable part of the total cost.

Our best tip

When comparing office options, always:

• Gather an overview of gross area, net area, and included shared facilities.

• Calculate estimated total costs (rent + shared costs).

• Evaluate the value of shared areas in relation to your company’s culture and needs.

This gives you a solid decision-making basis and ensures you are comparing office spaces fairly. The space with the lowest price per m² is not necessarily the one that gives the best value – it’s the relationship between gross, net, and actual usability that matters.

Summary

The difference between gross and net area can have a major impact on what you actually get for your rental money. While the gross area includes shared spaces, the net area is the space you can use exclusively. The difference can be significant, and the cost of shared spaces should be carefully considered in relation to the value they provide for your business. By understanding these definitions and factoring in shared costs, you’ll be better prepared when negotiating and selecting office space.

About the author
This article was written by Lauritz Kittelsen, Advisor at Spacefinder. He specializes in office consultancy and helps small and medium-sized companies find or lease office spaces.