diff --git a/example/runtime_unit.cpp b/example/runtime_unit.cpp
new file mode 100644
index 0000000..5777fac
--- /dev/null
+++ b/example/runtime_unit.cpp
@@ -0,0 +1,116 @@
+// Boost.Units - A C++ library for zero-overhead dimensional analysis and 
+// unit/quantity manipulation and conversion
+//
+// Copyright (C) 2003-2008 Matthias Christian Schabel
+// Copyright (C) 2008 Steven Watanabe
+//
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <map>
+#include <iostream>
+#include <boost/lexical_cast.hpp>
+#include <boost/units/quantity.hpp>
+#include <boost/units/cmath.hpp>
+#include <boost/units/systems/si/length.hpp>
+#include <boost/units/base_units/imperial/foot.hpp>
+
+//[runtime_unit_snippet_1
+
+namespace {
+
+using namespace boost::units;
+using imperial::foot_base_unit;
+
+std::map<std::string, quantity<si::length> > known_units;
+
+}
+
+quantity<si::length> calculate(const quantity<si::length>& t) 
+{
+    return(boost::units::hypot(t, 2.0 * si::meters));
+}
+
+int main() 
+{
+    known_units["meter"] = 1.0 * si::meters;
+    known_units["centimeter"] = .01 * si::meters;
+    known_units["foot"] =
+        conversion_factor(foot_base_unit::unit_type(), si::meter) * si::meter;
+        
+    std::string output_type("meter");
+    std::string input;
+    
+    while((std::cout << "> ") && (std::cin >> input)) 
+    {
+        if(!input.empty() && input[0] == '#') 
+        {
+            std::getline(std::cin, input);
+        }
+        else if(input == "exit") 
+        {
+            break;
+        }
+        else if(input == "help") 
+        {
+            std::cout << "type \"exit\" to exit\n"
+                "type \"return 'unit'\" to set the return units\n"
+                "type \"'number' 'unit'\" to do a simple calculation"
+                << std::endl;
+        } 
+        else if(input == "return") 
+        {
+            if(std::cin >> input) 
+            {
+                if(known_units.find(input) != known_units.end()) 
+                {
+                    output_type = input;
+                    std::cout << "Done." << std::endl;
+                } 
+                else 
+                {
+                    std::cout << "Unknown unit \"" << input << "\""
+                         << std::endl;
+                }
+            } 
+            else 
+            {
+                break;
+            }
+        } 
+        else 
+        {
+            try 
+            {
+                double value = boost::lexical_cast<double>(input);
+                
+                if(std::cin >> input) 
+                {
+                    if(known_units.find(input) != known_units.end()) 
+                    {
+                        std::cout << static_cast<double>(
+                            calculate(value * known_units[input]) /
+                            known_units[output_type])
+                            << ' ' << output_type << std::endl;
+                    } 
+                    else 
+                    {
+                        std::cout << "Unknown unit \"" << input << "\""
+                            << std::endl;
+                    }
+                } 
+                else 
+                {
+                    break;
+                }
+            } 
+            catch(...) 
+            {
+                std::cout << "Input error" << std::endl;
+            }
+        }
+    }
+}
+
+//]