diff --git a/include/units/Vector3D.hpp b/include/units/Vector3D.hpp
index 1bae018..37262ff 100644
--- a/include/units/Vector3D.hpp
+++ b/include/units/Vector3D.hpp
@@ -64,7 +64,7 @@ template <isQuantity T> class Vector3D {
          * @param other vector to add
          * @return Vector3D<T>
          */
-        Vector3D<T> operator+(Vector3D<T>& other) { return Vector3D<T>(x + other.x, y + other.y, z + other.z); }
+        Vector3D<T> operator+(Vector3D<T>& other) const { return Vector3D<T>(x + other.x, y + other.y, z + other.z); }
 
         /**
          * @brief - operator overload
@@ -75,7 +75,7 @@ template <isQuantity T> class Vector3D {
          * @param other vector to subtract
          * @return Vector3D<T>
          */
-        Vector3D<T> operator-(Vector3D<T>& other) { return Vector3D<T>(x - other.x, y - other.y, z - other.z); }
+        Vector3D<T> operator-(Vector3D<T>& other) const { return Vector3D<T>(x - other.x, y - other.y, z - other.z); }
 
         /**
          * @brief * operator overload
@@ -86,7 +86,7 @@ template <isQuantity T> class Vector3D {
          * @param factor scalar to multiply by
          * @return Vector3D<T>
          */
-        Vector3D<T> operator*(double factor) { return Vector3D<T>(x * factor, y * factor, z * factor); }
+        Vector3D<T> operator*(double factor) const { return Vector3D<T>(x * factor, y * factor, z * factor); }
 
         /**
          * @brief / operator overload
@@ -97,7 +97,7 @@ template <isQuantity T> class Vector3D {
          * @param factor scalar to divide by
          * @return Vector3D<T>
          */
-        Vector3D<T> operator/(double factor) { return Vector3D<T>(x / factor, y / factor, z / factor); }
+        Vector3D<T> operator/(double factor) const { return Vector3D<T>(x / factor, y / factor, z / factor); }
 
         /**
          * @brief += operator overload
@@ -176,7 +176,7 @@ template <isQuantity T> class Vector3D {
          * @param other the vector to calculate the dot product with
          * @return R the dot product
          */
-        template <isQuantity Q, isQuantity R = Multiplied<T, Q>> R dot(Vector3D<Q>& other) {
+        template <isQuantity Q, isQuantity R = Multiplied<T, Q>> R dot(Vector3D<Q>& other) const {
             return (x * other.x) + (y * other.y) + (z * other.z);
         }
 
@@ -193,7 +193,7 @@ template <isQuantity T> class Vector3D {
          * @param other the vector to calculate the cross product with
          * @return Vector3D<R> the cross product
          */
-        template <isQuantity Q, isQuantity R = Multiplied<T, Q>> Vector3D<R> cross(Vector3D<Q>& other) {
+        template <isQuantity Q, isQuantity R = Multiplied<T, Q>> Vector3D<R> cross(Vector3D<Q>& other) const {
             return Vector3D<R>(y * other.z - z * other.y, z * other.x - x * other.z, x * other.y - y * other.x);
         }
 
@@ -202,7 +202,7 @@ template <isQuantity T> class Vector3D {
          *
          * @return Angle
          */
-        Vector3D<Angle> theta() {
+        Vector3D<Angle> theta() const {
             const T mag = magnitude();
             return Vector3D<Angle>(acos(x / mag), acos(y / mag), acos(z / mag));
         }
@@ -212,7 +212,7 @@ template <isQuantity T> class Vector3D {
          *
          * @return T
          */
-        T magnitude() { return sqrt(square(x) + square(y) + square(z)); }
+        T magnitude() const { return sqrt(square(x) + square(y) + square(z)); }
 
         /**
          * @brief difference between two vectors
@@ -225,7 +225,7 @@ template <isQuantity T> class Vector3D {
          * @param other the other vector
          * @return Vector3D<T>
          */
-        Vector3D<T> vectorTo(Vector3D<T>& other) { return Vector2D<T>(other.x - x, other.y - y, other.z - z); }
+        Vector3D<T> vectorTo(Vector3D<T>& other) const { return Vector2D<T>(other.x - x, other.y - y, other.z - z); }
 
         /**
          * @brief the angle between two vectors
@@ -233,7 +233,7 @@ template <isQuantity T> class Vector3D {
          * @param other the other vector
          * @return Angle
          */
-        Angle angleTo(Vector3D<T>& other) { return units::acos(dot(other) / (magnitude() * other.magnitude())); }
+        Angle angleTo(Vector3D<T>& other) const { return units::acos(dot(other) / (magnitude() * other.magnitude())); }
 
         /**
          * @brief get the distance between two vectors
@@ -241,7 +241,7 @@ template <isQuantity T> class Vector3D {
          * @param other the other vector
          * @return T
          */
-        T distanceTo(Vector3D<T>& other) { return vectorTo(other).magnitude(); }
+        T distanceTo(Vector3D<T>& other) const { return vectorTo(other).magnitude(); }
 
         /**
          * @brief normalize the vector
@@ -286,7 +286,7 @@ template <isQuantity T> class Vector3D {
          * @param angle
          * @return Vector3D<T>
          */
-        Vector3D<T> rotatedBy(Vector3D<Angle> angle) {
+        Vector3D<T> rotatedBy(Vector3D<Angle> angle) const {
             T m = magnitude();
             Angle t = theta() + angle;
             return fromPolar(t, m);
@@ -298,7 +298,7 @@ template <isQuantity T> class Vector3D {
          * @param angle
          * @return Vector3D<T>
          */
-        Vector3D<T> rotatedTo(Angle angle) {
+        Vector3D<T> rotatedTo(Angle angle) const {
             T m = magnitude();
             return fromPolar(angle, m);
         }