diff --git a/docs/src/fortran/lib/constants.rst b/docs/src/fortran/lib/constants.rst
index dcd1631c..67c3ebf2 100644
--- a/docs/src/fortran/lib/constants.rst
+++ b/docs/src/fortran/lib/constants.rst
@@ -9,7 +9,7 @@ View source code :source:`fortran/include/constants.f90`
     :type: integer
 .. f:variable:: i4t
     :type: integer
-.. f:variable:: i19t
+.. f:variable:: i18t
     :type: integer
 
     A set of digit type constraints that denote how many decimal digits a number can support.
diff --git a/docs/src/fortran/lib/utils.rst b/docs/src/fortran/lib/utils.rst
index 23a279b5..e1fac6d5 100644
--- a/docs/src/fortran/lib/utils.rst
+++ b/docs/src/fortran/lib/utils.rst
@@ -27,9 +27,9 @@ View source code :source:`fortran/include/utils.f90`
 
     This stores the answer to a generic problem, storing multiple potential types. If the type field contains
     :f:var:`errort`, there was an error in generating the answer. If it is :f:var:`int64t`, it holds data of
-    type ``integer(i19t)``. If it is :f:var:`stringt`, it holds an allocatable character array.
+    type ``integer(i18t)``. If it is :f:var:`stringt`, it holds an allocatable character array.
 
-    :f integer(i19t) int_value:
+    :f integer(i18t) int_value:
     :f character(len=:) string_value:
     :fattrs string_value: allocatable
     :f integer(i1d) type:
diff --git a/fortran/src/include/constants.f90 b/fortran/src/include/constants.f90
index c8944904..329b2793 100644
--- a/fortran/src/include/constants.f90
+++ b/fortran/src/include/constants.f90
@@ -3,7 +3,7 @@ module constants
 
     integer, parameter :: i1t = selected_int_kind(1)
     integer, parameter :: i4t = selected_int_kind(4)
-    integer, parameter :: i19t = selected_int_kind(19)
+    integer, parameter :: i18t = selected_int_kind(18)
 
     integer(i1t), parameter :: errort = 0
     integer(i1t), parameter :: int64t = 1
diff --git a/fortran/src/include/utils.f90 b/fortran/src/include/utils.f90
index 90bb1c0a..7c7b0d7b 100644
--- a/fortran/src/include/utils.f90
+++ b/fortran/src/include/utils.f90
@@ -4,7 +4,7 @@ module utils
     implicit none
 
     type :: AnswerT
-        integer(i19t) :: int_value
+        integer(i18t) :: int_value
         character(len=:), allocatable :: string_value
         integer(i1t) :: type
     end type AnswerT
@@ -51,7 +51,7 @@ end function get_data_file
     function get_answer(id) result(answer)
         type(AnswerT) :: answer
         integer(i4t), intent(in) :: id
-        integer(i19t) :: i, j
+        integer(i18t) :: i, j
         integer :: ios, row_start, row_end, line_length
         character(len=:), allocatable :: text
         character(len=32) :: val