diff --git a/jerry-core/ecma/base/ecma-globals.h b/jerry-core/ecma/base/ecma-globals.h
index 3e1f3b5ab..170e4c5bc 100644
--- a/jerry-core/ecma/base/ecma-globals.h
+++ b/jerry-core/ecma/base/ecma-globals.h
@@ -734,7 +734,7 @@ typedef double ecma_number_t;
 /**
  * Maximum number of characters in string representation of ecma-uint32
  */
-#define ECMA_MAX_CHARS_IN_STRINGIFIED_UINT32 32
+#define ECMA_MAX_CHARS_IN_STRINGIFIED_UINT32 10
 
 /**
  * Maximum value of valid array index
diff --git a/jerry-core/ecma/base/ecma-helpers-conversion.c b/jerry-core/ecma/base/ecma-helpers-conversion.c
index fc294f83f..d741d734b 100644
--- a/jerry-core/ecma/base/ecma-helpers-conversion.c
+++ b/jerry-core/ecma/base/ecma-helpers-conversion.c
@@ -783,29 +783,25 @@ ecma_uint32_to_utf8_string (uint32_t value, /**< value to convert */
                             lit_utf8_byte_t *out_buffer_p, /**< buffer for string */
                             lit_utf8_size_t buffer_size) /**< size of buffer */
 {
-  const lit_utf8_byte_t digits[10] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
-
-  lit_utf8_byte_t *p = out_buffer_p + buffer_size - 1;
-  lit_utf8_size_t bytes_copied = 0;
+  lit_utf8_byte_t *buf_p = out_buffer_p + buffer_size;
 
   do
   {
-    JERRY_ASSERT (p >= out_buffer_p);
+    JERRY_ASSERT (buf_p >= out_buffer_p);
 
-    *p-- = digits[value % 10];
+    buf_p--;
+    *buf_p = (lit_utf8_byte_t) ((value % 10) + LIT_CHAR_0);
     value /= 10;
-
-    bytes_copied++;
   }
   while (value != 0);
 
-  p++;
+  JERRY_ASSERT (buf_p >= out_buffer_p);
 
-  JERRY_ASSERT (p >= out_buffer_p);
+  lit_utf8_size_t bytes_copied = (lit_utf8_size_t) (out_buffer_p + buffer_size - buf_p);
 
-  if (likely (p != out_buffer_p))
+  if (likely (buf_p != out_buffer_p))
   {
-    memmove (out_buffer_p, p, bytes_copied);
+    memmove (out_buffer_p, buf_p, bytes_copied);
   }
 
   return bytes_copied;
diff --git a/jerry-core/ecma/base/ecma-helpers-string.c b/jerry-core/ecma/base/ecma-helpers-string.c
index f64cfffcc..79c60f916 100644
--- a/jerry-core/ecma/base/ecma-helpers-string.c
+++ b/jerry-core/ecma/base/ecma-helpers-string.c
@@ -229,15 +229,25 @@ ecma_new_ecma_string_from_code_unit (ecma_char_t code_unit) /**< code unit */
 ecma_string_t *
 ecma_new_ecma_string_from_uint32 (uint32_t uint32_number) /**< UInt32-represented ecma-number */
 {
+  lit_utf8_byte_t byte_buf[ECMA_MAX_CHARS_IN_STRINGIFIED_UINT32];
+  lit_utf8_byte_t *buf_p = byte_buf + ECMA_MAX_CHARS_IN_STRINGIFIED_UINT32;
+
+  uint32_t value = uint32_number;
+  do
+  {
+    JERRY_ASSERT (buf_p >= byte_buf);
+
+    buf_p--;
+    *buf_p = (lit_utf8_byte_t) ((value % 10) + LIT_CHAR_0);
+    value /= 10;
+  }
+  while (value != 0);
+
+  lit_utf8_size_t size = (lit_utf8_size_t) (byte_buf + ECMA_MAX_CHARS_IN_STRINGIFIED_UINT32 - buf_p);
+
   ecma_string_t *string_desc_p = ecma_alloc_string ();
   string_desc_p->refs_and_container = ECMA_STRING_CONTAINER_UINT32_IN_DESC | ECMA_STRING_REF_ONE;
-
-  lit_utf8_byte_t byte_buf[ECMA_MAX_CHARS_IN_STRINGIFIED_UINT32];
-  lit_utf8_size_t bytes_copied = ecma_uint32_to_utf8_string (uint32_number,
-                                                             byte_buf,
-                                                             ECMA_MAX_CHARS_IN_STRINGIFIED_UINT32);
-
-  string_desc_p->hash = lit_utf8_string_calc_hash (byte_buf, bytes_copied);
+  string_desc_p->hash = lit_utf8_string_calc_hash (buf_p, size);
 
   string_desc_p->u.common_field = 0;
   string_desc_p->u.uint32_number = uint32_number;