diff --git a/server.c b/server.c
index 7711f97219ca18ce468140e59e5b799966f48357..95f03d7f3f8b9db6a8dd9fb379a40125a0503960 100644
--- a/server.c
+++ b/server.c
@@ -393,14 +393,14 @@ bool show_start_page(int sockfd, char* username) {
     // create added string
     strncpy(added, added_prefix, added_prefix_length);
     printf("added is now %s\r\n", added);
-    printf("added_len = %d\r\n", strlen(added));
+    printf("added_len = %ld\r\n", strlen(added));
     strncpy(added + added_prefix_length, username, username_length);
     printf("added is now %s\r\n", added);
-    printf("added_len = %d\r\n", strlen(added));
+    printf("added_len = %ld\r\n", strlen(added));
     strncpy(added + added_prefix_length + username_length, added_suffix,
             added_suffix_length);
     printf("added is now %s\r\n", added);
-    printf("added_len = %d\r\n", strlen(added));
+    printf("added_len = %ld\r\n", strlen(added));
 
     return show_modified_page(sockfd, START_PAGE, added, 212);
 }