Business Rates Measuring Methods

Clifford McDowell

The Valuation Office Agency uses three key measuring methods to help establish a properties business rates. These are Zoning, Net Internal Area and Gross Internal Area.


Zoning is a standard method of valuing and comparing retail premises. Shop or retail premises are divided into zones, starting from the window. Typically, each zone has a depth of 6.1 metres although this can vary depending on the location of the property.

Zones become less valuable the further they are from the window/entrance. Zone A, which is the closest, is the most valuable as it has the highest potential to generate business for the shop. Zone B is next, then Zone C. Anything after Zone C is usually defined as the remainder.

Survey method

The VOA uses standard measuring methods based on the Royal Institution of Chartered Surveyors (RICS) code of measuring practices.

This contains two common methods –

The net internal area (NIA) method of measurement is generally applied to:

  • offices
  • shops
  • other retail premises, such as banks, hairdressers, restaurants

The gross internal area (GIA) method of measurement is generally applied to industrial property such as warehouses or manufacturing units.

For urther information on Business Rates read our article on ‘How Business Rates are Calculated‘.


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