diff --git a/src/util.c b/src/util.c
index 665eca5..6d0d65c 100644
--- a/src/util.c
+++ b/src/util.c
@@ -66,10 +66,10 @@ void urlencode(const char *str, char *result) {
 char* safe_append(char *target, size_t *targetsize, const char *src) {
   size_t targetlen = strlen(target);
   size_t srclen = strlen(src);
-  size_t newsize = targetlen + 2*srclen + 1;
+  size_t newsize = 2*targetlen + srclen + 1;
 
   // check if reallocation is necessary
-  if((targetlen + srclen) > *targetsize) {
+  if((targetlen + srclen) >= *targetsize) {
     LOG(LVL_DEBUG, "safe_append: reallocating target string: %lu -> %lu characters", *targetsize, newsize);
 
     target = realloc(target, newsize * sizeof(char));