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, in order to comply with fire safety legislation.
Use our free fire extinguisher calculator below to determine how many extinguishers you need:
For any storey with a floor area of 400 m2 or less, there should be at least two extinguishers with a class A rating, having a combined minimum total fire rating of 26A – unless the area is very small.
For any storey with a floor area over 400 m2, there should also be at least two extinguishers with a class A rating, having a combined minimum total fire rating of 0.065 × floor area of the storey (in square metres).
Extinguishers should be placed near the fire hazard, but not so near they might be inaccessible or place the operator in undue danger in case of fire. They should be sited at a maximum travel distance of 30 metres from the hazard.
For special risks such as fires involving live electrical equipment, a suitable extinguisher should be provided, such as carbon dioxide or dry powder, within close distance of the risk (or at least within 30 m) usually placed next to the water extinguishers required.
There were 14,052 fires in non-residential buildings attended by the Fire and Rescue Service in 2025 – consistent with recent trends.