diff --git a/lib/fort.c b/lib/fort.c
index f8b85cd..9fb16c8 100644
--- a/lib/fort.c
+++ b/lib/fort.c
@@ -1780,7 +1780,7 @@ const char *ft_to_string(const ft_table_t *table)
     if (rows == 0)
         return EMPTY_STRING;
 
-    int written = 0;
+    size_t written = 0;
     int tmp = 0;
     size_t i = 0;
     context_t context;
diff --git a/src/fort_impl.c b/src/fort_impl.c
index 119c1e0..6360dae 100644
--- a/src/fort_impl.c
+++ b/src/fort_impl.c
@@ -624,7 +624,7 @@ const char *ft_to_string(const ft_table_t *table)
     if (rows == 0)
         return EMPTY_STRING;
 
-    int written = 0;
+    size_t written = 0;
     int tmp = 0;
     size_t i = 0;
     context_t context;