Thermal conductivity chart
Room-temperature thermal conductivity for common engineering materials, in both SI and imperial units. A higher value means the material moves heat faster, which is why copper and aluminum make good heat sinks and plastics make good insulators.
Thermal conductivity (k)
| Material | k (W/m·K) | k (BTU/hr·ft·°F) |
|---|---|---|
| Copper | 401 | 232 |
| Aluminum | 237 | 137 |
| Zinc | 116 | 67 |
| Brass | 109 | 63 |
| Nickel | 91 | 53 |
| Bronze | 60 | 35 |
| Cast iron | 55 | 32 |
| Carbon steel | 50 | 29 |
| Lead | 35 | 20 |
| Titanium | 22 | 12.7 |
| Stainless steel (304) | 16 | 9.4 |
| Concrete | 1.4 | 0.81 |
| Glass | 1.0 | 0.58 |
| Water | 0.6 | 0.35 |
| PTFE | 0.25 | 0.14 |
| Wood (pine) | 0.12 | 0.07 |
| Air | 0.026 | 0.015 |
Thermal conductivity (k) measures how readily a material conducts heat. High-k metals like copper and aluminum move heat quickly; low-k materials like wood, plastic, and air resist heat flow and work as insulators. Values are at about room temperature and shift with temperature and alloy.
Comparing how materials move and resist heat?
See the Thermal Expansion Coefficients chart, or browse the engineering calculators.
What thermal conductivity tells you
Conductivity k sets how much heat flows through a material for a given thickness and temperature difference. Double the k and you double the heat flow. Copper at 401 W/m-K conducts heat roughly 25 times faster than stainless steel, which is why cookware often has a copper or aluminum core inside a stainless shell.
Conductors and insulators
Metals conduct heat well because their free electrons carry energy quickly. Non-metals rely on slower vibration of atoms, so they conduct poorly and make good insulators. Trapped air has very low conductivity, which is why foams, fiberglass, and double glazing insulate so effectively.
FAQ
Which metal conducts heat best?
Of common metals, copper at about 401 W/m-K, followed by aluminum at 237. Silver is slightly higher than copper but rarely used for bulk heat transfer.
Why does stainless steel feel cold but conduct poorly?
It feels cold because it pulls heat from your skin faster than air does, but its conductivity near 16 W/m-K is low for a metal, roughly 25 times below copper.
Does thermal conductivity change with temperature?
Yes. For most metals it falls slightly as temperature rises, while for many non-metals it rises. The values here are typical room-temperature figures.