diff --git a/mingw-w64-crt/misc/mbrtowc.c b/mingw-w64-crt/misc/mbrtowc.c
index be5830a..75c9f98 100644
--- a/mingw-w64-crt/misc/mbrtowc.c
+++ b/mingw-w64-crt/misc/mbrtowc.c
@@ -68,8 +68,12 @@
   /* Length of potential multibyte character */
   int length = 1;
 
+  /* Number of bytes consumed from `mbs` */
+  int bytes_consumed = 0;
+
   if (conversion_state.bytes[0]) {
     conversion_state.bytes[1] = mbs[0];
+    bytes_consumed = 1;
     length = 2;
   } else if (mb_cur_max == 2 && isleadbyte (mbs[0])) {
     conversion_state.bytes[0] = mbs[0];
@@ -81,9 +85,11 @@
     }
 
     conversion_state.bytes[1] = mbs[1];
+    bytes_consumed = 2;
     length = 2;
   } else {
     conversion_state.bytes[0] = mbs[0];
+    bytes_consumed = 1;
   }
 
   /* Store terminating '\0' */
@@ -116,7 +122,7 @@
     *state = 0;
   }
 
-  return length;
+  return bytes_consumed;
 
 eilseq:
   errno = EILSEQ;
diff --git a/mingw-w64-crt/testcases/t_mbrlen.c b/mingw-w64-crt/testcases/t_mbrlen.c
index 4d297e3..2e723a1 100644
--- a/mingw-w64-crt/testcases/t_mbrlen.c
+++ b/mingw-w64-crt/testcases/t_mbrlen.c
@@ -118,12 +118,9 @@
 
   /**
    * Complete multibyte character
-   *
-   * NOTE: return value does not conform to ISO C and POSIX.
-   * This behavior is implemented for consistency with CRT.
    */
 
-  assert (mbrlen ((char *) Multibyte + 1, 1, &state) == 2);
+  assert (mbrlen ((char *) Multibyte + 1, 1, &state) == 1);
   assert (mbsinit (&state));
   assert (errno == 0);
 
diff --git a/mingw-w64-crt/testcases/t_mbrtowc.c b/mingw-w64-crt/testcases/t_mbrtowc.c
index 1b94207..cb11b14 100644
--- a/mingw-w64-crt/testcases/t_mbrtowc.c
+++ b/mingw-w64-crt/testcases/t_mbrtowc.c
@@ -136,13 +136,10 @@
 
   /**
    * Complete multibyte character
-   *
-   * NOTE: return value does not conform to ISO C and POSIX.
-   * This behavior is implemented for consistency with CRT.
    */
   wc = WEOF;
 
-  assert (mbrtowc (&wc, (char *) Multibyte + 1, 1, &state) == 2);
+  assert (mbrtowc (&wc, (char *) Multibyte + 1, 1, &state) == 1);
   assert (wc != WEOF);
   assert (mbsinit (&state));
   assert (errno == 0);