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Thermal Conductivity & Specific Heat Converter

Convert the two key thermal properties of a material, kept separate because they measure different things. Thermal conductivity (k) is how fast heat flows through a material for a given temperature gradient — high for metals, low for insulation, in watts per metre-kelvin. Specific heat capacity (c) is how much energy it takes to warm a given mass by one degree, in joules per kilogram-kelvin. Choose a property, then convert between SI, calorie and BTU-based units.

How to use this tool

  1. Choose which property you are converting: thermal conductivity or specific heat.
  2. Enter the value.
  3. Pick the unit you have and the unit you want — the menus update for the chosen property.
  4. Read the result and the full list of equivalents.
  5. Note the two properties never inter-convert; they describe different things.

The formula

Thermal conductivity and specific heat are separate properties. Conductivity (k) sets how fast heat flows through a material; specific heat (c) sets how much energy raises its temperature. This tool converts each between unit systems.

conductivity k: W/(m·K) [heat flow per gradient] specific heat c: J/(kg·K) [energy per mass per degree]
k
Thermal conductivity, W/(m·K)
c
Specific heat capacity, J/(kg·K)

A good conductor like copper has high k; a good insulator has low k. Water’s high specific heat is why it is used to store and move heat.

Worked examples

Copper conductivity

Given
401 W/(m·K)
Result
≈ 231.7 BTU/(h·ft·°F)

Copper is an excellent conductor; converting to imperial gives about 232 BTU per hour-foot-°F.

Water specific heat

Given
4184 J/(kg·K)
Result
1 cal/(g·°C)

Water’s specific heat is 4184 J/(kg·K), which is exactly 1 calorie per gram per degree — the calorie’s original definition.

Insulation

Given
0.04 W/(m·K)
Result
≈ 0.277 BTU·in/(h·ft²·°F)

Mineral wool insulation is around 0.04 W/(m·K), a very low conductivity, which is the point of insulation.

Frequently asked questions

Conductivity is about the rate heat flows through a material; specific heat is about how much energy it takes to change its temperature. A material can conduct heat quickly yet need little energy to warm, or the reverse — they are independent properties.

Water needs a lot of energy to change temperature — 4184 joules per kilogram per degree — so it stores and carries heat effectively and moderates temperature swings. That is why it is used as a coolant and why coastal climates are milder.

Copper is about 400 W/(m·K), aluminium around 235, stainless steel near 15, water about 0.6, and insulating foams under 0.05. The range across materials spans four orders of magnitude, which is why material choice matters so much in heat management.

Both the calorie and the BTU were defined around raising a unit mass of water by one degree, so 1 cal/(g·°C) and 1 BTU/(lb·°F) both equal 4184 J/(kg·K). Water’s specific heat is 1 in both of those legacy systems by construction.

They are exact ratios between defined units — the calorie and BTU have fixed joule values. The tool preserves full internal precision and rounds only the displayed figure, so no accuracy is lost in the conversion itself.

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