A surface light guide has a radiation exit area extending along a main extension plane of the surface light guide and is provided for laterally coupling radiation. The surface light guide includes scattering locations for scattering the coupled radiation. The surface light guide includes a first boundary surface and a second boundary surface which delimit the light conductance of the coupled-in radiation in the vertical direction. A first layer and a second layer are formed on each other in the vertical direction between the first boundary surface and the second boundary surface. Further disclosed are a planar emitter including at least one surface light guide.