Fireplace Flue Size Calculator
Enter the details of your fireplace into the boxes below. If you have a hood above your fireplace then your need to add up the lengths of all sides of the hood that are open (usually the front and sides) and enter that in the width box.
All measurements are in mm.
This calculator is for quick reference only. Round liners for fireplaces only come in standard sizes of 200mm, 230mm, 250mm, and 300mm. Please contact us to discuss this in depth and refer to the document J building regulations page 24/25. The building regulations are available on our stove building regs page.
