Fire Extinguisher Calculator

Portable fire extinguishers are the most common type of fire fighting equipment to be found in commercial and industrial premises. However in order to be compliant with fire safety law, the overall number of extinguishers you require is dependent upon the size of your premises.

The fire extinguisher calculator is a tool designed to work out how many extinguishers your workplace requires by area, to comply with fire safety legislation.

Use our free fire extinguisher calculator below to determine how many extinguishers you need:

Approximate floor area (m²):

Requirements for a floor area of

Fire “A” Rating required:

Extinguishers required:

Disclaimer: This calculator is only to be used as guidance and does not provide the definitive answer.

The fire rating is found by multiplying the floor area in metres squared (m²) by 0.065. Therefore for a floor area of 200m² the fire rating is 200 x 0.065 = 13A.

A 9 litre water extinguisher has a fire rating of 13A, therefore one 9 litre water extinguisher will be required for every 200m² of floor area.

For special risks such as fires involving live electrical equipment, a suitable extinguisher should be provided – carbon dioxide or dry powder, within close distance of the risk (or at least within 30m) usually placed next to the water extinguishers required.

There were 11,916 non-residential fires attended by the Fire and Rescue Service in 2020/21 – consistent with recent trends.

We provide on-site fire extinguisher training through our IOSH, NEBOSH, BAFE, and GIFireE qualified consultants.

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