The ** Q_{10} temperature coefficient** is a measure of the rate of change of a biological or chemical system as a consequence of increasing the temperature by 10 °C. There are many examples where the

*Q*

_{10}is used, one being the calculation of the nerve conduction velocity and another being calculating the contraction velocity of muscle fibres. It can also be applied to chemical reactions and many other systems.

The *Q*_{10} is calculated as:

where

*R*is the rate*T*is the temperature in Celsius degrees or kelvins.

*Q*_{10} is a unitless quantity, as it is the factor by which a rate changes, and is a useful way to express the temperature dependence of a process.

For most biological systems, the *Q*_{10} value is ~ 2 to 3.