Free Online Insulation U-value Calculator

Our U-value calculator gives you instant access to calculating a proposed insulation thickness and product selection or giving an indicative calculation on a proposed construction detail.

U-value Calculator
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Use the calculator

Our free online U-value calculator covers a variety of different insulation applications for our Celotex products.

Specify your desired U-value before immediately calculating the required insulation thickness and product selection, using our pitched roofs, ceilings, ground floor and wall insulation calculator.

Work through your own construction detail to get an early indication of the U-value that this might achieve.

To access the U value insulation calculator, and download your calculation PDFs, you must log in to the Members Area, if you’re not already a member, it is quick and easy to register!


Register now to use the Calculator Calculator Icon

Further information

If you require further help or guidance on an already created U-value calculation or for bespoke calculations and would like to speak with an advisor, please contact our Technical Support Team on 01473 820850.

Lines are open Monday – Friday, from 9.00am – 5pm.

Please note, some products in the U-value calculator may not be available from stock, or be subject to minimum order quantities and extended lead times.