Wikipedia says that Planck's law is:
$$B_\nu (\nu, T) = \frac{2h\nu^3}{c^2}\times \frac{1}{e^{h\nu /(k_BT)} - 1}$$
So, to convert this to wavelength, I substituted $\nu = \frac{c}{\lambda}$ which gave me:
$$B_\lambda(\lambda, T) = \frac{2hc}{\lambda^3}\times \frac{1}{e^{hc/(\lambda k_BT)} - 1}$$
However, Wikipedia says that:
$$B_\lambda(\lambda, T) = \frac{2hc^2}{\lambda^5}\times \frac{1}{e^{hc/(\lambda k_BT)} - 1}$$
What did I do wrong?