diff --git a/pathfinder/model/dot.py b/pathfinder/model/dot.py
index e0ee759..9e6ed6d 100644
--- a/pathfinder/model/dot.py
+++ b/pathfinder/model/dot.py
@@ -35,3 +35,24 @@ class Dot():
 		# Will throw problems for irregular points, but that's okay for now.
 		chunked_pts = [pts[i: i + pt_length] for i in range(0, len(pts), pt_length)]
 		return sum(self.v_for_point(pt) for pt in chunked_pts) - self.v
+
+	def jac_pt(self, pt: numpy.ndarray) -> numpy.ndarray:
+		p = pt[0:3]  # hardcoded here because chances
+		s = pt[3:6]  # are we'll only ever work in 3d.
+
+		diff = self.r - s
+
+		p_divs = diff / (numpy.linalg.norm(diff)**3)
+
+		r_divs = -p / (numpy.linalg.norm(diff)**3) + 3 * p.dot(diff) * diff / (numpy.linalg.norm(diff)**5)
+
+		return numpy.append(p_divs, r_divs)
+
+	def jac(self, pts: numpy.ndarray) -> numpy.ndarray:
+		# 6 because dipole in 3d has 6 degrees of freedom.
+		pt_length = 6
+		# creates numpy.ndarrays in groups of pt_length.
+		# Will throw problems for irregular points, but that's okay for now.
+		chunked_pts = [pts[i: i + pt_length] for i in range(0, len(pts), pt_length)]
+
+		return numpy.append([], [self.jac_pt(pt) for pt in chunked_pts])
diff --git a/tests/model/test_dot.py b/tests/model/test_dot.py
index 7be9185..858d958 100644
--- a/tests/model/test_dot.py
+++ b/tests/model/test_dot.py
@@ -23,3 +23,23 @@ def test_dot_v_from_dipole():
 
 	numpy.testing.assert_allclose(dot.v_for_point(pt), target, err_msg="v from dipole at a dot was incorrect!")
 	numpy.testing.assert_allclose(dot.cost(pt), cost, err_msg="cost from dipole at a dot was incorrect!")
+
+
+def test_dot_jac():
+	# for a dot located at (1, 2, 3)
+	dot = model.Dot(50, (1, 2, 3))
+
+	# and dipole located at (4, 7, 11) with p=(8, 9, 10)
+	pt = numpy.array((8, 9, 10, 4, 7, 11))
+
+	target_jac_pt = [-0.003092303707812889, -0.005153839513021483, -0.00824614322083437, 0.0058585481811285, 0.01423090787983279, 0.02730483137919137]
+
+	# assume a second dipole at (12, 13, -5), with p = (-1, -2, -3)
+	second_target = [-0.002054993939616119, -0.002054993939616119, 0.001494541046993541, 5.494636202182148e-6, 0.0001923122670763748, 0.0006923241614749492]
+	pt2 = numpy.array((-1, -2, -3, 12, 13, -5))
+	jac_row_target = target_jac_pt + second_target
+	pts = numpy.append(pt, pt2)
+
+	assert len(dot.jac_pt(pt)) == 6
+	numpy.testing.assert_allclose(dot.jac_pt(pt), target_jac_pt, err_msg="Jac pt doesn't match Mathematica result.")
+	numpy.testing.assert_allclose(dot.jac(pts), jac_row_target, err_msg="whole row should match")