diff --git a/Snakefile b/Snakefile
index 751bca6bf98cc1b6512b922074399d58027876ca..b6d6b225167414cac0b4d966626544037351de8e 100644
--- a/Snakefile
+++ b/Snakefile
@@ -24,7 +24,7 @@ TODO: Discuss how wavelet details should be plotted
 
 Urgent:
 TODO: Mark Burgers' equation as inviscid -> Done
-TODO: Make sure CFL number is absolute value
+TODO: Make sure CFL number is absolute value -> Done
 TODO: Make sure only ghost cells are limited for Dirichlet boundary
 TODO: Move height adjustment and stretch factor into implicit solver function
 TODO: Check correctness of implicit solver (with burgex.f)
diff --git a/scripts/tcd/Equation.py b/scripts/tcd/Equation.py
index 84e854b35c3e69c6484f1334bda571f831353bff..569a4e4a6405cda3da32ab56cb394721717a2711 100644
--- a/scripts/tcd/Equation.py
+++ b/scripts/tcd/Equation.py
@@ -273,7 +273,7 @@ class LinearAdvection(Equation):
         # Adjust for final time-step
         if current_time+time_step > self.final_time:
             time_step = self.final_time-current_time
-            cfl_number = self.wave_speed * time_step / self._mesh.cell_len
+            cfl_number = abs(self.wave_speed * time_step / self._mesh.cell_len)
 
         return cfl_number, time_step