Page Size - Paginating GridView Yii2

Create a file PageSize.php , copy code below into it.

class PageSize extends \yii\base\Widget {

    /**
     * @var string the label text.
     */
    public $label = 'Show ';

    /**
     * @var integer the defualt page size. This page size will be used when the $_GET['pageSize'] is empty.
     */
    const DefaultPageSize = 10;

    /**
     * @var string the name of the GET request parameter used to specify the size of the page.
     * This will be used as the input name of the dropdown list with page size options.
     */
    public $pageSizeParam = 'pageSize';

    /**
     * @var array the list of page sizes
     */
    public $sizes = [5 => 5, 10 => 10, 15 => 15, 20 => 20, 25 => 25, 50 => 50, 100 => 100];

    /**
     * @var string the template to be used for rendering the output.
     */
    public $template = '{label} {list} entries';

    /**
     * @var array the list of options for the drop down list.
     */
    public $options;

    /**
     * @var array the list of options for the label
     */
    public $labelOptions;

    /**
     * @var boolean whether to encode the label text.
     */
    public $encodeLabel = true;

    /**
     * Runs the widget and render the output
     */
    public function run() {
        if (empty($this->options['id'])) {
            $this->options['id'] = $this->id;
        }

        if ($this->encodeLabel) {
            $this->label = Html::encode($this->label);
        }
        $perPage = !empty($_GET[$this->pageSizeParam]) ? $_GET[$this->pageSizeParam] : self::DefaultPageSize;
        $listHtml = Html::dropDownList('pageSize', $perPage, $this->sizes, $this->options);
        $labelHtml = Html::label($this->label, $this->options['id'], $this->labelOptions);
        $output = str_replace(['{list}', '{label}'], [$listHtml, $labelHtml], $this->template);

        return $output;
    }

}

In GridView you can call below code:

/* ~~~
 *
 * and set the `filterSelector` property of GridView as shown in
 * following example.
 *
 * ~~~
 *  $dataProvider,
 *      'filterModel' => $searchModel,
 *      'filterSelector' => 'select[name="pageSize"]', //Copy this code
 *      'columns' => [
 *          ...
 *      ],
 *  ]); ?>
 * ~~~
 */