1 files changed, 2 insertions, 0 deletions
diff --git a/sprintf.c b/sprintf.c
index c5334b1f9f..cf8ea20de6 100644
--- a/sprintf.c
+++ b/sprintf.c
@@ -729,6 +729,8 @@ rb_f_sprintf(argc, argv)
 		    need = strlen(expr);
 		    if ((!isnan(fval) && fval < 0.0) || (flags & FPLUS))
 			need++;
+		    else if (flags & FSPACE)
+			need++;
 		    if ((flags & FWIDTH) && need < width)
 			need = width;