diff --git a/ext2spice/ext2hier.c b/ext2spice/ext2hier.c
index f066f672..e03b647a 100644
--- a/ext2spice/ext2hier.c
+++ b/ext2spice/ext2hier.c
@@ -304,7 +304,7 @@ spcHierWriteParams(hc, dev, scale, l, w, sdM)
 		if (esScale < 0)
 		    fprintf(esSpiceF, "%g", w * scale);
 		else if (plist->parm_scale != 1.0)
-		    fprintf(esSpiceF, "%g", w * scale * esScale
+		    fprintf(esSpiceF, "%g", (double)w * scale * esScale
 				* plist->parm_scale * 1E-6);
 		else
 		    esSIvalue(esSpiceF, 1.0E-6 * (w + plist->parm_offset)