diff --git a/framework/i18n/Formatter.php b/framework/i18n/Formatter.php
index 28c84024f9..6229974161 100644
--- a/framework/i18n/Formatter.php
+++ b/framework/i18n/Formatter.php
@@ -176,10 +176,10 @@ class Formatter extends Component
             $this->locale = Yii::$app->language;
         }
         if ($this->booleanFormat === null) {
-            $this->booleanFormat = [Yii::t('yii', 'No'), Yii::t('yii', 'Yes')];
+            $this->booleanFormat = [Yii::t('yii', 'No', [], $this->locale), Yii::t('yii', 'Yes', [], $this->locale)];
         }
         if ($this->nullDisplay === null) {
-            $this->nullDisplay = '<span class="not-set">' . Yii::t('yii', '(not set)') . '</span>';
+            $this->nullDisplay = '<span class="not-set">' . Yii::t('yii', '(not set)', [], $this->locale) . '</span>';
         }
         $this->_intlLoaded = extension_loaded('intl');
         if (!$this->_intlLoaded) {
@@ -470,14 +470,14 @@ class Formatter extends Component
      */
     private $_phpNameToPattern = [
         'short' => [
-            'date' => 'd.m.Y',
+            'date' => 'n/j/y',
             'time' => 'H:i',
-            'datetime' => 'd.m.Y H:i',
+            'datetime' => 'n/j/y H:i',
         ],
         'medium' => [
             'date' => 'M j, Y',
-            'time' => 'H:i:s',
-            'datetime' => 'M j, Y H:i:s',
+            'time' => 'g:i:s A',
+            'datetime' => 'M j, Y g:i:s A',
         ],
         'long' => [
             'date' => 'F j, Y',
@@ -612,9 +612,6 @@ class Formatter extends Component
      */
     private function convertPatternIcuToPhp($pattern)
     {
-        if (isset($this->_dateFormats[$pattern])) {
-            return $pattern;
-        }
         return strtr($pattern, [
             'dd' => 'd',    // day with leading zeros
             'd' => 'j',     // day without leading zeros
@@ -688,9 +685,6 @@ class Formatter extends Component
      */
     private function convertPatternPhpToIcu($pattern)
     {
-        if (isset($this->_dateFormats[$pattern])) {
-            return $pattern;
-        }
         return strtr($pattern, [
             'd' => 'dd',    // day with leading zeros
             'j' => 'd',     // day without leading zeros
@@ -828,40 +822,40 @@ class Formatter extends Component
 
         if ($interval->invert) {
             if ($interval->y >= 1) {
-                return Yii::t('yii', 'in {delta, plural, =1{a year} other{# years}}', ['delta' => $interval->y]);
+                return Yii::t('yii', 'in {delta, plural, =1{a year} other{# years}}', ['delta' => $interval->y], $this->locale);
             }
             if ($interval->m >= 1) {
-                return Yii::t('yii', 'in {delta, plural, =1{a month} other{# months}}', ['delta' => $interval->m]);
+                return Yii::t('yii', 'in {delta, plural, =1{a month} other{# months}}', ['delta' => $interval->m], $this->locale);
             }
             if ($interval->d >= 1) {
-                return Yii::t('yii', 'in {delta, plural, =1{a day} other{# days}}', ['delta' => $interval->d]);
+                return Yii::t('yii', 'in {delta, plural, =1{a day} other{# days}}', ['delta' => $interval->d], $this->locale);
             }
             if ($interval->h >= 1) {
-                return Yii::t('yii', 'in {delta, plural, =1{an hour} other{# hours}}', ['delta' => $interval->h]);
+                return Yii::t('yii', 'in {delta, plural, =1{an hour} other{# hours}}', ['delta' => $interval->h], $this->locale);
             }
             if ($interval->i >= 1) {
-                return Yii::t('yii', 'in {delta, plural, =1{a minute} other{# minutes}}', ['delta' => $interval->i]);
+                return Yii::t('yii', 'in {delta, plural, =1{a minute} other{# minutes}}', ['delta' => $interval->i], $this->locale);
             }
 
-            return Yii::t('yii', 'in {delta, plural, =1{a second} other{# seconds}}', ['delta' => $interval->s]);
+            return Yii::t('yii', 'in {delta, plural, =1{a second} other{# seconds}}', ['delta' => $interval->s], $this->locale);
         } else {
             if ($interval->y >= 1) {
-                return Yii::t('yii', '{delta, plural, =1{a year} other{# years}} ago', ['delta' => $interval->y]);
+                return Yii::t('yii', '{delta, plural, =1{a year} other{# years}} ago', ['delta' => $interval->y], $this->locale);
             }
             if ($interval->m >= 1) {
-                return Yii::t('yii', '{delta, plural, =1{a month} other{# months}} ago', ['delta' => $interval->m]);
+                return Yii::t('yii', '{delta, plural, =1{a month} other{# months}} ago', ['delta' => $interval->m], $this->locale);
             }
             if ($interval->d >= 1) {
-                return Yii::t('yii', '{delta, plural, =1{a day} other{# days}} ago', ['delta' => $interval->d]);
+                return Yii::t('yii', '{delta, plural, =1{a day} other{# days}} ago', ['delta' => $interval->d], $this->locale);
             }
             if ($interval->h >= 1) {
-                return Yii::t('yii', '{delta, plural, =1{an hour} other{# hours}} ago', ['delta' => $interval->h]);
+                return Yii::t('yii', '{delta, plural, =1{an hour} other{# hours}} ago', ['delta' => $interval->h], $this->locale);
             }
             if ($interval->i >= 1) {
-                return Yii::t('yii', '{delta, plural, =1{a minute} other{# minutes}} ago', ['delta' => $interval->i]);
+                return Yii::t('yii', '{delta, plural, =1{a minute} other{# minutes}} ago', ['delta' => $interval->i], $this->locale);
             }
 
-            return Yii::t('yii', '{delta, plural, =1{a second} other{# seconds}} ago', ['delta' => $interval->s]);
+            return Yii::t('yii', '{delta, plural, =1{a second} other{# seconds}} ago', ['delta' => $interval->s], $this->locale);
         }
     }
 
@@ -899,7 +893,8 @@ class Formatter extends Component
      * value is rounded automatically to the defined decimal digits.
      *
      * @param mixed $value the value to be formatted.
-     * @param integer $decimals the number of digits after the decimal point.
+     * @param integer $decimals the number of digits after the decimal point. If not given the number of digits is determined from the
+     * [[locale]] and if the [PHP intl extension](http://php.net/manual/en/book.intl.php) is not available defaults to `2`.
      * @param array $options optional configuration for the number formatter. This parameter will be merged with [[numberFormatterOptions]].
      * @param array $textOptions optional configuration for the number formatter. This parameter will be merged with [[numberFormatterTextOptions]].
      * @return string the formatted result.
@@ -1100,33 +1095,33 @@ class Formatter extends Component
         if ($binaryPrefix && $this->sizeFormat['base'] === 1024) {
             switch ($position) {
                 case 0:
-                    return $verbose ? Yii::t('yii', '{n, plural, =1{# byte} other{# bytes}}', $params) : Yii::t('yii', '{n} B', $params);
+                    return $verbose ? Yii::t('yii', '{n, plural, =1{# byte} other{# bytes}}', $params, $this->locale) : Yii::t('yii', '{n} B', $params, $this->locale);
                 case 1:
-                    return $verbose ? Yii::t('yii', '{n, plural, =1{# kibibyte} other{# kibibytes}}', $params) : Yii::t('yii', '{n} KiB', $params);
+                    return $verbose ? Yii::t('yii', '{n, plural, =1{# kibibyte} other{# kibibytes}}', $params, $this->locale) : Yii::t('yii', '{n} KiB', $params, $this->locale);
                 case 2:
-                    return $verbose ? Yii::t('yii', '{n, plural, =1{# mebibyte} other{# mebibytes}}', $params) : Yii::t('yii', '{n} MiB', $params);
+                    return $verbose ? Yii::t('yii', '{n, plural, =1{# mebibyte} other{# mebibytes}}', $params, $this->locale) : Yii::t('yii', '{n} MiB', $params, $this->locale);
                 case 3:
-                    return $verbose ? Yii::t('yii', '{n, plural, =1{# gibibyte} other{# gibibytes}}', $params) : Yii::t('yii', '{n} GiB', $params);
+                    return $verbose ? Yii::t('yii', '{n, plural, =1{# gibibyte} other{# gibibytes}}', $params, $this->locale) : Yii::t('yii', '{n} GiB', $params, $this->locale);
                 case 4:
-                    return $verbose ? Yii::t('yii', '{n, plural, =1{# tebibyte} other{# tebibytes}}', $params) : Yii::t('yii', '{n} TiB', $params);
+                    return $verbose ? Yii::t('yii', '{n, plural, =1{# tebibyte} other{# tebibytes}}', $params, $this->locale) : Yii::t('yii', '{n} TiB', $params, $this->locale);
                 default:
-                    return $verbose ? Yii::t('yii', '{n, plural, =1{# pebibyte} other{# pebibytes}}', $params) : Yii::t('yii', '{n} PiB', $params);
+                    return $verbose ? Yii::t('yii', '{n, plural, =1{# pebibyte} other{# pebibytes}}', $params, $this->locale) : Yii::t('yii', '{n} PiB', $params, $this->locale);
             }
         }
 
         switch ($position) {
             case 0:
-                return $verbose ? Yii::t('yii', '{n, plural, =1{# byte} other{# bytes}}', $params) : Yii::t('yii', '{n} B', $params);
+                return $verbose ? Yii::t('yii', '{n, plural, =1{# byte} other{# bytes}}', $params, $this->locale) : Yii::t('yii', '{n} B', $params, $this->locale);
             case 1:
-                return $verbose ? Yii::t('yii', '{n, plural, =1{# kilobyte} other{# kilobytes}}', $params) : Yii::t('yii', '{n} KB', $params);
+                return $verbose ? Yii::t('yii', '{n, plural, =1{# kilobyte} other{# kilobytes}}', $params, $this->locale) : Yii::t('yii', '{n} KB', $params, $this->locale);
             case 2:
-                return $verbose ? Yii::t('yii', '{n, plural, =1{# megabyte} other{# megabytes}}', $params) : Yii::t('yii', '{n} MB', $params);
+                return $verbose ? Yii::t('yii', '{n, plural, =1{# megabyte} other{# megabytes}}', $params, $this->locale) : Yii::t('yii', '{n} MB', $params, $this->locale);
             case 3:
-                return $verbose ? Yii::t('yii', '{n, plural, =1{# gigabyte} other{# gigabytes}}', $params) : Yii::t('yii', '{n} GB', $params);
+                return $verbose ? Yii::t('yii', '{n, plural, =1{# gigabyte} other{# gigabytes}}', $params, $this->locale) : Yii::t('yii', '{n} GB', $params, $this->locale);
             case 4:
-                return $verbose ? Yii::t('yii', '{n, plural, =1{# terabyte} other{# terabytes}}', $params) : Yii::t('yii', '{n} TB', $params);
+                return $verbose ? Yii::t('yii', '{n, plural, =1{# terabyte} other{# terabytes}}', $params, $this->locale) : Yii::t('yii', '{n} TB', $params, $this->locale);
             default:
-                return $verbose ? Yii::t('yii', '{n, plural, =1{# petabyte} other{# petabytes}}', $params) : Yii::t('yii', '{n} PB', $params);
+                return $verbose ? Yii::t('yii', '{n, plural, =1{# petabyte} other{# petabytes}}', $params, $this->locale) : Yii::t('yii', '{n} PB', $params, $this->locale);
         }
     }
 
diff --git a/tests/unit/framework/i18n/FormatterTest.php b/tests/unit/framework/i18n/FormatterTest.php
index 607e633ca6..8aaedb20d8 100644
--- a/tests/unit/framework/i18n/FormatterTest.php
+++ b/tests/unit/framework/i18n/FormatterTest.php
@@ -20,6 +20,7 @@ function extension_loaded($name)
 
 namespace yiiunit\framework\i18n;
 
+use yii\base\InvalidParamException;
 use yii\i18n\Formatter;
 use yiiunit\TestCase;
 use DateTime;
@@ -54,7 +55,8 @@ class FormatterTest extends TestCase
         }
 
         $this->mockApplication([
-            'timeZone' => 'UTC'
+            'timeZone' => 'UTC',
+            'language' => 'ru-RU',
         ]);
         $this->formatter = new Formatter(['locale' => 'en-US']);
     }
@@ -76,6 +78,17 @@ class FormatterTest extends TestCase
         $this->assertSame(date('Y-m-d', $value), $this->formatter->format($value, 'data'));
     }
 
+    public function testLocale()
+    {
+        // locale is configured explicitly
+        $f = new Formatter(['locale' => 'en-US']);
+        $this->assertEquals('en-US', $f->locale);
+
+        // if not, take from application
+        $f = new Formatter();
+        $this->assertEquals('ru-RU', $f->locale);
+    }
+
 
     public function testAsRaw()
     {
@@ -211,38 +224,39 @@ class FormatterTest extends TestCase
         $this->testAsDate();
     }
 
-    public function testIntlAsTime()
-    {
-        $this->testAsTime();
-    }
-
-    public function testIntlAsDatetime()
-    {
-        $this->testAsDatetime();
-    }
-
     public function testAsDate()
     {
         $value = time();
         $this->assertSame(date('M j, Y', $value), $this->formatter->asDate($value));
         $this->assertSame(date('Y/m/d', $value), $this->formatter->asDate($value, 'php:Y/m/d'));
-        $this->assertSame(date('d.m.Y', $value), $this->formatter->asDate($value, 'short'));
+        $this->assertSame(date('m/d/Y', $value), $this->formatter->asDate($value, 'MM/dd/yyyy'));
+        $this->assertSame(date('n/j/y', $value), $this->formatter->asDate($value, 'short'));
         $this->assertSame(date('F j, Y', $value), $this->formatter->asDate($value, 'long'));
 
         // null display
         $this->assertSame($this->formatter->nullDisplay, $this->formatter->asDate(null));
     }
 
+    public function testIntlAsTime()
+    {
+        $this->testAsTime();
+    }
+
     public function testAsTime()
     {
         $value = time();
         $this->assertSame(date('g:i:s A', $value), $this->formatter->asTime($value));
-        $this->assertSame(date('n:i:s A', $value), $this->formatter->asTime($value, 'php:n:i:s A'));
+        $this->assertSame(date('h:i:s A', $value), $this->formatter->asTime($value, 'php:h:i:s A'));
 
         // null display
         $this->assertSame($this->formatter->nullDisplay, $this->formatter->asTime(null));
     }
 
+    public function testIntlAsDatetime()
+    {
+        $this->testAsDatetime();
+    }
+
     public function testAsDatetime()
     {
         $value = time();
@@ -410,10 +424,8 @@ class FormatterTest extends TestCase
         $this->assertSame("123", $this->formatter->asInteger(123.23));
         $this->assertSame("123", $this->formatter->asInteger(123.53));
         $this->assertSame("0", $this->formatter->asInteger(0));
-        $this->assertSame("0", $this->formatter->asInteger('a'));
         $this->assertSame("-123", $this->formatter->asInteger(-123.23));
         $this->assertSame("-123", $this->formatter->asInteger(-123.53));
-        $this->assertSame("-123", $this->formatter->asInteger("-123abc"));
 
         $this->assertSame("123,456", $this->formatter->asInteger(123456));
         $this->assertSame("123,456", $this->formatter->asInteger(123456.789));
@@ -422,9 +434,59 @@ class FormatterTest extends TestCase
         $this->assertSame($this->formatter->nullDisplay, $this->formatter->asInteger(null));
     }
 
+    /**
+     * @expectedException \yii\base\InvalidParamException
+     */
+    public function testAsIntegerException()
+    {
+        $this->assertSame("0", $this->formatter->asInteger('a'));
+    }
+
+    /**
+     * @expectedException \yii\base\InvalidParamException
+     */
+    public function testAsIntegerException2()
+    {
+        $this->assertSame("0", $this->formatter->asInteger('-123abc'));
+    }
+
     public function testIntlAsDecimal()
     {
-        $this->testAsDecimal();
+        $value = 123.12;
+        $this->assertSame("123.12", $this->formatter->asDecimal($value, 2));
+        $this->assertSame("123.1", $this->formatter->asDecimal($value, 1));
+        $this->assertSame("123", $this->formatter->asDecimal($value, 0));
+
+        $value = 123;
+        $this->assertSame("123", $this->formatter->asDecimal($value));
+        $this->assertSame("123.00", $this->formatter->asDecimal($value, 2));
+        $this->formatter->decimalSeparator = ',';
+        $this->formatter->thousandSeparator = '.';
+        $value = 123.12;
+        $this->assertSame("123,12", $this->formatter->asDecimal($value));
+        $this->assertSame("123,1", $this->formatter->asDecimal($value, 1));
+        $this->assertSame("123", $this->formatter->asDecimal($value, 0));
+        $value = 123123.123;
+        $this->assertSame("123.123", $this->formatter->asDecimal($value, 0));
+        $this->assertSame("123.123,12", $this->formatter->asDecimal($value, 2));
+        $this->formatter->thousandSeparator = '';
+        $this->assertSame("123123,1", $this->formatter->asDecimal($value, 1));
+        $this->formatter->thousandSeparator = ' ';
+        $this->assertSame("12 31 23,1", $this->formatter->asDecimal($value, 1, [\NumberFormatter::GROUPING_SIZE => 2]));
+
+        $value = 123123.123;
+        $this->formatter->decimalSeparator = ',';
+        $this->formatter->thousandSeparator = ' ';
+        $this->assertSame("123 123", $this->formatter->asDecimal($value, 0));
+        $this->assertSame("123 123,12", $this->formatter->asDecimal($value, 2));
+
+        $this->formatter->decimalSeparator = null;
+        $this->formatter->thousandSeparator = null;
+        $value = '-123456.123';
+        $this->assertSame("-123,456.123", $this->formatter->asDecimal($value));
+
+        // null display
+        $this->assertSame($this->formatter->nullDisplay, $this->formatter->asDecimal(null));
     }
 
     public function testAsDecimal()
@@ -443,21 +505,22 @@ class FormatterTest extends TestCase
         $this->assertSame("123", $this->formatter->asDecimal($value, 0));
         $value = 123123.123;
         $this->assertSame("123.123,12", $this->formatter->asDecimal($value));
-        $this->assertSame("123123,12", $this->formatter->asDecimal($value, 2, null, false));
 
         $value = 123123.123;
-        $this->assertSame("123,123", $this->formatter->asDecimal($value));
-        $this->assertSame("123,123.12", $this->formatter->asDecimal($value, 2));
+        $this->assertSame("123.123,12", $this->formatter->asDecimal($value));
+        $this->assertSame("123.123,12", $this->formatter->asDecimal($value, 2));
         $this->formatter->decimalSeparator = ',';
         $this->formatter->thousandSeparator = ' ';
-        $this->assertSame("123 123", $this->formatter->asDecimal($value));
+        $this->assertSame("123 123,12", $this->formatter->asDecimal($value));
         $this->assertSame("123 123,12", $this->formatter->asDecimal($value, 2));
         $this->formatter->thousandSeparator = '';
-        $this->assertSame("123123", $this->formatter->asDecimal($value));
+        $this->assertSame("123123,12", $this->formatter->asDecimal($value));
         $this->assertSame("123123,12", $this->formatter->asDecimal($value, 2));
 
+        $this->formatter->decimalSeparator = null;
+        $this->formatter->thousandSeparator = null;
         $value = '-123456.123';
-        $this->assertSame("-123,456.123", $this->formatter->asDecimal($value));
+        $this->assertSame("-123,456.123", $this->formatter->asDecimal($value, 3));
 
         // null display
         $this->assertSame($this->formatter->nullDisplay, $this->formatter->asDecimal(null));
@@ -470,12 +533,12 @@ class FormatterTest extends TestCase
 
     public function testAsPercent()
     {
-        $value = '123';
-        $this->assertSame('12,300%', $this->formatter->asPercent($value));
-        $value = '0.1234';
-        $this->assertSame("12%", $this->formatter->asPercent($value));
-        $value = '-0.009343';
-        $this->assertSame("-1%", $this->formatter->asPercent($value));
+        $this->assertSame('12,300%', $this->formatter->asPercent(123));
+        $this->assertSame('12,300%', $this->formatter->asPercent('123'));
+        $this->assertSame("12%", $this->formatter->asPercent(0.1234));
+        $this->assertSame("12%", $this->formatter->asPercent('0.1234'));
+        $this->assertSame("-1%", $this->formatter->asPercent(-0.009343));
+        $this->assertSame("-1%", $this->formatter->asPercent('-0.009343'));
 
         // null display
         $this->assertSame($this->formatter->nullDisplay, $this->formatter->asPercent(null));
@@ -508,13 +571,13 @@ class FormatterTest extends TestCase
         $this->formatter->currencyCode = 'USD';
         $this->assertSame('USD 123.00', $this->formatter->asCurrency('123'));
         $this->assertSame('USD 0.00', $this->formatter->asCurrency('0'));
-        $this->assertSame('USD -123.45', $this->formatter->asCurrency('-123,45'));
+        $this->assertSame('USD -123.45', $this->formatter->asCurrency('-123.45'));
         $this->assertSame('USD -123.45', $this->formatter->asCurrency(-123.45));
 
         $this->formatter->currencyCode = 'EUR';
         $this->assertSame('EUR 123.00', $this->formatter->asCurrency('123'));
         $this->assertSame('EUR 0.00', $this->formatter->asCurrency('0'));
-        $this->assertSame('EUR -123.45', $this->formatter->asCurrency('-123,45'));
+        $this->assertSame('EUR -123.45', $this->formatter->asCurrency('-123.45'));
         $this->assertSame('EUR -123.45', $this->formatter->asCurrency(-123.45));
 
         // null display
@@ -522,11 +585,6 @@ class FormatterTest extends TestCase
     }
 
     public function testIntlAsScientific()
-    {
-        $this->testAsScientific();
-    }
-
-    public function testAsScientific()
     {
         $value = '123';
         $this->assertSame('1.23E2', $this->formatter->asScientific($value));
@@ -539,6 +597,19 @@ class FormatterTest extends TestCase
         $this->assertSame($this->formatter->nullDisplay, $this->formatter->asScientific(null));
     }
 
+    public function testAsScientific()
+    {
+        $value = '123';
+        $this->assertSame('1.23E+2', $this->formatter->asScientific($value, 2));
+        $value = '123456';
+        $this->assertSame("1.234560E+5", $this->formatter->asScientific($value));
+        $value = '-123456.123';
+        $this->assertSame("-1.234561E+5", $this->formatter->asScientific($value));
+
+        // null display
+        $this->assertSame($this->formatter->nullDisplay, $this->formatter->asScientific(null));
+    }
+
     public function testIntlAsSpellout()
     {
         $this->assertSame('one hundred twenty-three', $this->formatter->asSpellout(123));