diff --git a/core/script/builtin.js b/core/script/builtin.js
--- a/core/script/builtin.js
+++ b/core/script/builtin.js
@@ -27,7 +27,7 @@
     for (i = 0; i < cFields.length; i++)
     {
         var field = Doc.getField( cFields[i] );
-        var val = Number( field.value );
+        var val = util.stringToNumber( field.value );
 
         if ( cFunction === "SUM" || cFunction === "AVG" )
         {
@@ -58,5 +58,74 @@
         ret /= cFields.length;
     }
 
+    event.value = util.numberToString( ret, "g", 32 );
+}
+
+
+/** AFNumber_Format
+ *
+ * Formats event.value based on parameters.
+ *
+ * Parameter description based on Acrobat Help:
+ *
+ * nDec is the number of places after the decimal point.
+ *
+ * sepStyle is an integer denoting whether to use a separator
+ *          If it is 1 comma should be used.
+ *          If it is 2 a dot should be used.
+ *          The decimal seperator is changed accordingly.
+ *
+ * nexStyle is the formatting used for negative numbers: - not implemented.
+ * 0 = MinusBlack
+ * 1 = Red
+ * 2 = ParensBlack
+ * 3 = ParensRed
+ *
+ * currStyle is the currency style - not used.
+ *
+ * strCurrency is the currency symbol.
+ *
+ * bCurrencyPrepend is true to prepend the currency symbol;
+ *  false to display on the end of the number.
+ */
+function AFNumber_Format( nDec, sepStyle, negStyle, currStyle, strCurrency, bCurrencyPrepend )
+{
+    if ( !event.value )
+    {
+        return;
+    }
+
+    var ret;
+    var localized = util.stringToNumber( event.value );
+
+    if ( sepStyle === 2 )
+    {
+        // Use de_DE as the locale for the dot seperator format
+        ret = util.numberToString( localized, "f", nDec, 'de_DE' );
+    }
+    else
+    {
+        // Otherwise US
+        ret = util.numberToString( localized, "f", nDec, 'en_US' );
+    }
+
+    if ( sepStyle === 0 )
+    {
+        // No seperators. Remove all commas from the US format.
+        ret.replace( /,/g, '' );
+    }
+
+    if ( strCurrency )
+    {
+        if ( bCurrencyPrepend )
+        {
+            ret = strCurrency + ret;
+        }
+        else
+        {
+            ret = ret + strCurrency;
+        }
+    }
+
     event.value = ret;
 }
diff --git a/core/script/kjs_util.cpp b/core/script/kjs_util.cpp
--- a/core/script/kjs_util.cpp
+++ b/core/script/kjs_util.cpp
@@ -15,6 +15,9 @@
 #include <kjs/kjsarguments.h>
 
 #include <QUrl>
+#include <QLocale>
+
+#include <cmath>
 
 using namespace Okular;
 
@@ -56,15 +59,97 @@
     return obj;
 }
 
+/** Converts a Number to a String using l10n
+ *
+ * String numberToString( Number number, String format = 'g', int precision = 6,
+ *                        String LocaleName = system )
+ */
+static KJSObject numberToString ( KJSContext *context, void *,
+                                  const KJSArguments &arguments )
+{
+    if ( arguments.count() < 1 )
+    {
+        return context->throwException( QStringLiteral( "Invalid arguments" ) );
+    }
+
+    double number = arguments.at( 0 ).toNumber( context );
+    if ( std::isnan( number ) )
+    {
+        return KJSString( "NaN" );
+    }
+
+    QChar format = QLatin1Char( 'g' );
+    if ( arguments.count() >= 2 )
+    {
+        const QString fmt = arguments.at( 1 ).toString( context );
+        if ( fmt.size() )
+        {
+            format = fmt[0];
+        }
+    }
+
+    int precision = 6;
+    if ( arguments.count() >= 3 )
+    {
+        precision = arguments.at( 2 ).toInt32( context );
+    }
+
+    QLocale locale;
+    if ( arguments.count() == 4 )
+    {
+        locale = QLocale( arguments.at( 3 ).toString( context ) );
+    }
+
+    // While we want to localize we don't want to loose precision
+    // after the default of 6 significant digits
+    return KJSString( locale.toString( number, format.toLatin1(), precision ) );
+}
+
+/** Converts a String to a Number using l10n.
+ *
+ * Number stringToNumber( String number, String LocaleName = system ) */
+static KJSObject stringToNumber ( KJSContext *context, void *,
+                                  const KJSArguments &arguments )
+{
+    if ( arguments.count() < 1 )
+    {
+        return context->throwException( QStringLiteral( "Invalid arguments" ) );
+    }
+
+    QString number = arguments.at( 0 ).toString( context );
+    if ( number.isEmpty() )
+    {
+        return KJSNumber( 0 );
+    }
+
+    QLocale locale;
+    if ( arguments.count() == 2 )
+    {
+        locale = QLocale( arguments.at( 1 ).toString( context ) );
+    }
+
+    bool ok;
+    double converted = locale.toDouble( number, &ok );
+
+    if ( !ok )
+    {
+        return KJSNumber( std::nan( "" ) );
+    }
+
+    return KJSNumber( converted );
+}
+
 void JSUtil::initType( KJSContext *ctx )
 {
     static bool initialized = false;
     if ( initialized )
         return;
     initialized = true;
 
     g_utilProto = new KJSPrototype();
-    g_utilProto->defineFunction( ctx, QStringLiteral("crackURL"), crackURL );
+    g_utilProto->defineFunction( ctx, QStringLiteral( "crackURL" ), crackURL );
+    g_utilProto->defineFunction( ctx, QStringLiteral( "stringToNumber" ), stringToNumber );
+    g_utilProto->defineFunction( ctx, QStringLiteral( "numberToString" ), numberToString );
 }
 
 KJSObject JSUtil::object( KJSContext *ctx )