Cooker Hood Extraction Calculator

This tool compares a cooker hood's airflow figures against a common air-change sizing rule and the Approved Document F minimum for England, using figures you type in; nothing you enter leaves your browser.

Kitchen dimensions

Length (metres)

Width (metres)

Ceiling height (metres)

Extraction type

Hood vents to outside (ducted)

Hood recirculates air back into the room

Hood airflow by speed

Enter the airflow from the hood's data sheet, in cubic metres per hour, for each speed. The boost row is optional; leave it blank if the hood does not have one.

Installed duct airflow (optional)

Airflow for the duct run as installed (m³/h) Only fill this in if the installation instructions give a separate figure for the duct as fitted. It will be used for the top speed instead of its data sheet figure above.

Air-change sizing multiplier

Multiplier (room volume × this number = sizing figure) Defaults to 10, a sizing rule used by some extraction guides. Change it if your source gives a different figure.

Room volume

Air-change sizing figure

Approved Document F minimum

How each speed compares

Speed	Airflow used	Meets Part F minimum	Meets air-change figure

These figures are for England only. The hood maker's installation instructions and your local building control decide what applies to your own kitchen. Scotland, Wales and Northern Ireland publish their own separate rules.