diff --git a/include/openmc/output.h b/include/openmc/output.h
index e396c07d8..793c9b727 100644
--- a/include/openmc/output.h
+++ b/include/openmc/output.h
@@ -4,6 +4,7 @@
 #ifndef OPENMC_OUTPUT_H
 #define OPENMC_OUTPUT_H
 
+#include <string>
 
 namespace openmc {
 
@@ -16,6 +17,14 @@ namespace openmc {
 
 void header(const char* msg, int level);
 
+
+//==============================================================================
+//! Retrieve a time stamp with the format "yyyy-mm-dd hh:mm:ss"
+//!
+//==============================================================================
+ 
+std::string time_stamp();
+ 
 //==============================================================================
 //! Display information regarding cell overlap checking.
 //==============================================================================
diff --git a/src/output.cpp b/src/output.cpp
index 6a3abeed6..0eb6b204c 100644
--- a/src/output.cpp
+++ b/src/output.cpp
@@ -5,6 +5,7 @@
 #include <iomanip>  // for setw
 #include <iostream>
 #include <sstream>
+#include <ctime>
 
 #include "openmc/cell.h"
 #include "openmc/geometry.h"
@@ -39,6 +40,18 @@ header(const char* msg, int level) {
   }
 }
 
+std::string time_stamp()
+{
+  int base_year = 1990;
+  std::stringstream ts;
+  std::time_t t = std::time(0);   // get time now
+  std::tm* now = std::localtime(&t);
+  ts << now->tm_year + base_year << "-" << now->tm_mon
+     << "-" << now->tm_mday << " " << now->tm_hour
+     << ":" << now->tm_min << ":" << now->tm_sec;
+  return ts.str();
+}
+  
 //==============================================================================
 
 void print_overlap_check() {
diff --git a/src/plot.cpp b/src/plot.cpp
index ea0fda83f..afb927252 100644
--- a/src/plot.cpp
+++ b/src/plot.cpp
@@ -1,5 +1,4 @@
 #include <fstream>
-#include <ctime>
 
 #include "openmc/plot.h"
 #include "openmc/constants.h"
@@ -14,6 +13,7 @@
 #include "openmc/output.h"
 #include "openmc/hdf5_interface.h"
 #include "openmc/random_lcg.h"
+#include "openmc/output.h"
 
 namespace openmc {
 
@@ -28,16 +28,6 @@ const int NULLRGB[3] = {0, 0, 0};
 // RUN_PLOT controls the logic for making one or many plots
 //===============================================================================
 
-  std::string time_stamp()
-  {
-    std::stringstream ts;
-    std::time_t t = std::time(0);   // get time now
-    std::tm* now = std::localtime(&t);
-    ts << now->tm_year + 1990 << "-" << now->tm_mon
-       << "-" << now->tm_mday << " " << now->tm_hour
-       << ":" << now->tm_min << ":" << now->tm_sec;
-    return ts.str();
-  }
 
 int openmc_plot_geometry_c() {
   int err;