Calculators
Thermal insulation
Calculate R-value, U-value, insulation thickness, dew point and whole insulation packs with clear SI and US units.
Calculators
Dew point calculatorCalculate air dew point from temperature and humidity, and compare it with a separately measured surface temperature.Layered thermal resistanceNominal R and U for entered homogeneous layers.Insulation thickness calculatorCalculate insulation thickness in mm and inches from your target RSI or US R-value and product lambda, k-value or R per inch.R-value calculator: thickness and conductivityCalculate insulation R-value from thickness and lambda, US k-value or R per inch. Enter mm, metres, inches or feet and compare RSI with US R.R-value to U-value calculatorConvert R-value to U-value or U-factor and back. Compare US and SI units, RSI, formulas and worked examples.Insulation packsFull insulation packs from measured area, layer count, coverage and allowance.
Essential guides
View all guides- Lambda values for EPS, XPS and mineral woolRead product lambda, declared and design values. Compare documented EPS, XPS and mineral wool examples and calculate layer R correctly.
- How to calculate U-value from layersAdd homogeneous layer resistances, account for surface resistances and check the limits of a nominal U-value calculation.
- Dew point and condensation limitationsAir dew point is not an interstitial-condensation or mould assessment.
About this category
Use these tools for focused quantity estimates. Review the scope and limitations shown with each calculator before using a result for purchasing or planning.