diff --git a/framework/yii/base/Formatter.php b/framework/yii/base/Formatter.php
index d15e5f2..e62039e 100644
--- a/framework/yii/base/Formatter.php
+++ b/framework/yii/base/Formatter.php
@@ -39,17 +39,19 @@ class Formatter extends Component
 	public $datetimeFormat = 'Y/m/d h:i:s A';
 	/**
 	 * @var array the text to be displayed when formatting a boolean value. The first element corresponds
-	 * to the text display for false, the second element for true. Defaults to <code>array('No', 'Yes')</code>.
+	 * to the text display for false, the second element for true. Defaults to `array('No', 'Yes')`.
 	 */
 	public $booleanFormat;
 	/**
 	 * @var string the character displayed as the decimal point when formatting a number.
+	 * If not set, "." will be used.
 	 */
-	public $decimalSeparator = '.';
+	public $decimalSeparator;
 	/**
 	 * @var string the character displayed as the thousands separator character when formatting a number.
+	 * If not set, "," will be used.
 	 */
-	public $thousandSeparator = ',';
+	public $thousandSeparator;
 
 
 	/**
@@ -273,7 +275,11 @@ class Formatter extends Component
 	 */
 	public function asDouble($value, $decimals = 2)
 	{
-		return str_replace('.', $this->decimalSeparator, sprintf("%.{$decimals}f", $value));
+		if ($this->decimalSeparator === null) {
+			return sprintf("%.{$decimals}f", $value);
+		} else {
+			return str_replace('.', $this->decimalSeparator, sprintf("%.{$decimals}f", $value));
+		}
 	}
 
 	/**
@@ -287,6 +293,8 @@ class Formatter extends Component
 	 */
 	public function asNumber($value, $decimals = 0)
 	{
-		return number_format($value, $decimals, $this->decimalSeparator, $this->thousandSeparator);
+		$ds = isset($this->decimalSeparator) ? $this->decimalSeparator: '.';
+		$ts = isset($this->thousandSeparator) ? $this->thousandSeparator: ',';
+		return number_format($value, $decimals, $ds, $ts);
 	}
 }
diff --git a/framework/yii/i18n/Formatter.php b/framework/yii/i18n/Formatter.php
index 4a93397..8fa29dd 100644
--- a/framework/yii/i18n/Formatter.php
+++ b/framework/yii/i18n/Formatter.php
@@ -54,6 +54,16 @@ class Formatter extends \yii\base\Formatter
 	 * creating a new number formatter to format decimals, currencies, etc.
 	 */
 	public $numberFormatOptions = array();
+	/**
+	 * @var string the character displayed as the decimal point when formatting a number.
+	 * If not set, the decimal separator corresponding to [[locale]] will be used.
+	 */
+	public $decimalSeparator;
+	/**
+	 * @var string the character displayed as the thousands separator character when formatting a number.
+	 * If not set, the thousand separator corresponding to [[locale]] will be used.
+	 */
+	public $thousandSeparator;
 
 
 	/**
@@ -70,6 +80,16 @@ class Formatter extends \yii\base\Formatter
 		if ($this->locale === null) {
 			$this->locale = Yii::$app->language;
 		}
+		if ($this->decimalSeparator === null || $this->thousandSeparator === null) {
+			$formatter = new NumberFormatter($this->locale, NumberFormatter::DECIMAL);
+			if ($this->decimalSeparator === null) {
+				$this->decimalSeparator = $formatter->getSymbol(NumberFormatter::GROUPING_SEPARATOR_SYMBOL);
+			}
+			if ($this->thousandSeparator === null) {
+				$this->thousandSeparator = $formatter->getSymbol(NumberFormatter::DECIMAL_SEPARATOR_SYMBOL);
+			}
+		}
+
 		parent::init();
 	}