diff --git a/src/multipole.h b/src/multipole.h
index 138914235974305337ed34164ea86e0c68a73f40..f3020f21870424f0867cbab50eaf6a8ac6949553 100644
--- a/src/multipole.h
+++ b/src/multipole.h
@@ -43,7 +43,9 @@
 
 struct grav_tensor {
 
-  double F_000;
+  /* 0th order terms */
+  float F_000;
+
 #if SELF_GRAVITY_MULTIPOLE_ORDER > 0
 
   /* 1st order terms */