diff --git a/contrib/block_time.pl b/contrib/block_time.pl
index dff43ea4e..b4b039a60 100755
--- a/contrib/block_time.pl
+++ b/contrib/block_time.pl
@@ -9,6 +9,11 @@ my $block      = shift || die "Usage: $0 123";
 my $hush       = "./src/hush-cli";
 my $blockcount = qx{$hush getblockcount};
 
+unless ($blockcount = int($blockcount)) {
+    print "Invalid response from hush-cli\n";
+    exit 1;
+}
+
 if ($block <= $blockcount) {
 	die "That block has already happened!";
 } else {