diff --git a/sources/hash.F90 b/sources/hash.F90
index 1a60142..389f426 100644
--- a/sources/hash.F90
+++ b/sources/hash.F90
@@ -99,7 +99,7 @@ module hash
 
 !-------------------------------------------------------------------------------
 !
-    length    = size(input)
+    length    = size(input, kind=8)
     hash      = 0_8
     offset    = 1_8
     remaining = length