diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 5ce466fa9ec7..c73d75fdf83e 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,9 @@
+2017-02-16  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/60936
+	* src/c++11/snprintf_lite.cc (__concat_size_t): Calculate length
+	written to buffer, not length remaining in buffer.
+
 2017-02-15  Tim Shen  <timshen@google.com>
 
 	PR libstdc++/78723
diff --git a/libstdc++-v3/src/c++11/snprintf_lite.cc b/libstdc++-v3/src/c++11/snprintf_lite.cc
index 1a408ca1d8f7..de132d92dd49 100644
--- a/libstdc++-v3/src/c++11/snprintf_lite.cc
+++ b/libstdc++-v3/src/c++11/snprintf_lite.cc
@@ -81,7 +81,7 @@ namespace __gnu_cxx {
 	__val /= 10;
       }
     while (__val != 0);
-    size_t __len = __out - __cs;
+    size_t __len = __cs + __ilen - __out;
     if (__bufsize < __len)
       return -1;