You can compute it using Fourier's law. It states that the rate of heat transfer through conduction is directly proportional to the thermal gradient (dT/dx). Mathematically,

q_x = - k * A * dT / dx (1D conduction)

where,

q_x - rate of heat transfer in x direction

k - thermal conductivity of the material

A - area normal to the direction of heat transfer

dT / dx - thermal gradient

The minus sign is necessary because heat is transferred in the direction of decreasing temperature.