diff --git a/sxt/base64.c b/sxt/base64.c
index bec8c70..75dacbf 100644
--- a/sxt/base64.c
+++ b/sxt/base64.c
@@ -22,6 +22,7 @@
 
 #include <stdint.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/types.h>
 
 #include <sxt/base64.h>
@@ -80,7 +81,7 @@ size_t sxt_b64encode_in(const char *data, char *bdata, size_t data_len)
       nil = (c + 3) - data_len;
       len = 0;
       for(i = 0; i < 3; i++) {
-        if(i < nil) {
+        if(i < nil + 1) {
           ib[i] = *((unsigned char *)data + (c + i));
           len++;
         } else ib[i] = (unsigned char)0;