diff --git a/src/coordinax/_coordinax/base.py b/src/coordinax/_coordinax/base.py
index de9c5158..9cec27d2 100644
--- a/src/coordinax/_coordinax/base.py
+++ b/src/coordinax/_coordinax/base.py
@@ -321,6 +321,26 @@ def T(self) -> "Self":  # noqa: N802
         """
         return replace(self, **{k: v.T for k, v in field_items(self)})
 
+    @property
+    def dim(self) -> int:
+        """The dimensionality of the vector.
+
+        Examples
+        --------
+        We assume the following imports:
+
+        >>> from unxt import Quantity
+        >>> import coordinax as cx
+
+        We can get the dimensionality of a vector:
+
+        >>> vec = cx.CartesianPosition2D.constructor([1, 2], "m")
+        >>> vec.dim
+        2
+
+        """
+        return len(self.components)
+
     # ---------------------------------------------------------------
     # Methods
 
diff --git a/tests/test_base.py b/tests/test_base.py
index d558cfcf..e06978d5 100644
--- a/tests/test_base.py
+++ b/tests/test_base.py
@@ -101,6 +101,10 @@ def test_shape(self, vector):
             *(getattr(vector, c).shape for c in vector.components)
         )
 
+    def test_dim(self, vector):
+        """Test :meth:`AbstractVector.dim`."""
+        assert f"{vector.dim}D" in vector.__class__.__name__
+
     def test_flatten(self, vector):
         """Test :meth:`AbstractVector.flatten`."""
         # Test input vector
@@ -183,7 +187,7 @@ class AbstractPositionTest(AbstractVectorTest):
     """Test :class:`coordinax.AbstractPosition`."""
 
     @pytest.fixture(scope="class")
-    def vector(self) -> AbstractPosition:  # noqa: PT004
+    def vector(self) -> AbstractPosition:
         """Return a vector."""
         raise NotImplementedError
 
@@ -206,12 +210,12 @@ class AbstractVelocityTest(AbstractVectorTest):
     """Test :class:`coordinax.AbstractVelocity`."""
 
     @pytest.fixture(scope="class")
-    def vector(self) -> AbstractPosition:  # noqa: PT004
+    def vector(self) -> AbstractPosition:
         """Return a vector."""
         raise NotImplementedError
 
     @pytest.fixture(scope="class")
-    def difntl(self) -> AbstractVelocity:  # noqa: PT004
+    def difntl(self) -> AbstractVelocity:
         """Return a vector."""
         raise NotImplementedError