diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 7713f73e66b0..fffa9e1cfc94 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -54,7 +54,7 @@ int string_get_size(u64 size, u64 blk_size, const enum string_size_units units,
 	static const unsigned int rounding[] = { 500, 50, 5 };
 	int i = 0, j;
 	u32 remainder = 0, sf_cap;
-	char tmp[8];
+	char tmp[12];
 	const char *unit;
 
 	tmp[0] = '\0';