diff --git a/crates/fj-math/src/bivector.rs b/crates/fj-math/src/bivector.rs
index a4b70ceda..b5c5788d9 100644
--- a/crates/fj-math/src/bivector.rs
+++ b/crates/fj-math/src/bivector.rs
@@ -1,4 +1,4 @@
-use crate::Vector;
+use crate::{Scalar, Vector};
 
 /// # An n-dimensional bivector
 ///
@@ -27,3 +27,12 @@ pub struct Bivector<const D: usize> {
     /// The second of the vectors whose outer product defines this bivector
     pub b: Vector<D>,
 }
+
+impl<const D: usize> Bivector<D> {
+    /// Compute the magnitude of the bivector
+    pub fn magnitude(&self) -> Scalar {
+        self.a.angle_to(&self.b).sin().abs()
+            * self.a.magnitude()
+            * self.b.magnitude()
+    }
+}