diff --git a/lib/http_request.c b/lib/http_request.c
index 2a1936e..e259a60 100644
--- a/lib/http_request.c
+++ b/lib/http_request.c
@@ -276,7 +276,7 @@ http_request_get_header_string(http_request_t *request, char **header_str)
     assert(str);
     *header_str = str;
     char *p = str;
-    int n = sizeof(str);
+    int n = len + 1;
     for (int i = 0; i < request->headers_size; i++) {
         int hlen = strlen(request->headers[i]); 
         snprintf(p, n, "%s", request->headers[i]);
diff --git a/lib/utils.c b/lib/utils.c
index 9ba21f5..07788ec 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -191,7 +191,7 @@ char *utils_data_to_string(const unsigned char *data, int datalen, int chars_per
     char *str = (char *) calloc(len + 1, sizeof(char));
     assert(str);
     char *p = str;
-    int n = sizeof(str);
+    int n = len + 1;
     for (int i = 0; i < datalen; i++) {
         if (i > 0 && i % chars_per_line == 0) {
             snprintf(p, n, "\n");