diff --git a/kwant/continuum/landau_levels.py b/kwant/continuum/landau_levels.py
index 90544579724c1afa56cf061b6b94b96395e735a8..13e70c4e6b7224d3dab456d5a4497587514ea8af 100644
--- a/kwant/continuum/landau_levels.py
+++ b/kwant/continuum/landau_levels.py
@@ -95,6 +95,13 @@ def discretize_landau(hamiltonian, N, momenta=None, grid_spacing=1):
         'hamiltonian' discretized in a basis of Landau levels in the plane
         defined by 'momenta'. If a third coordinate is present in 'hamiltonian',
         then this also has a translational symmetry in that coordinate direction.
+        The builder has a parameter 'B' in addition to any other parameters
+        present in the provided 'hamiltonian'.
+
+    Notes
+    -----
+    The units of magnetic field are :math:`ϕ₀ / 2 π a²` with :math:`ϕ₀ = h/e`
+    the magnetic flux quantum and :math:`a` the unit length.
     """
 
     if N <= 0: