diff --git a/bluemira/magnetostatics/greens.py b/bluemira/magnetostatics/greens.py
index 4823a6166b..1f364710ac 100644
--- a/bluemira/magnetostatics/greens.py
+++ b/bluemira/magnetostatics/greens.py
@@ -475,6 +475,8 @@ def greens_all(
     a, k2 = calc_a_k2(xc, zc, x, z)
     e, k = calc_e_k(k2)
     i1, i2 = calc_i1_i2(a, k2, e, k)
+    i1 *= 4
+    i2 *= 4
     a_part = (z - zc) ** 2 + x**2 + xc**2
     b_part = -2 * x * xc
     g_bx = MU_0_4PI * xc * (z - zc) * (i1 - i2 * a_part) / b_part