diff --git a/maths.h b/maths.h
index b864db8..01d98da 100644
--- a/maths.h
+++ b/maths.h
@@ -1,3 +1,6 @@
+#ifndef MATHS_H
+#define MATHS_H
+
 #include "turret.h"
 
 double degToRad(double deg);
@@ -6,3 +9,5 @@ void angleToStep(Turret::StepRatio stepRatio, vec2<double> angle,
                  vec2<long> &step);
 void cartesianToPolar(Turret::StepRatio stepRatio, Turret::Offset offset,
                       vec2<long> zero, vec3<double> position, vec2<long> &step);
+
+#endif