diff --git a/swiftest/init_cond.py b/swiftest/init_cond.py
index 72d33d3ab..30b292d5e 100644
--- a/swiftest/init_cond.py
+++ b/swiftest/init_cond.py
@@ -66,7 +66,7 @@ def get_Gmass(raw_response):
                     M = M.split('=')[1].strip().split(' ')[0].strip()
                     M = float(M)  * mult * unit_conv
                     try:
-                        return M * swiftest.GC
+                        return M * swiftest.GC * 1e-9 # Return units of km**3 / s**2 for consistency
                     except:
                         return None
             return None
@@ -537,4 +537,4 @@ def vec2xr(param: Dict, **kwargs: Any):
                             )
         ds = xr.combine_by_coords([ds, clm_xr])
 
-    return ds
\ No newline at end of file
+    return ds