diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d5039d4..3a6a0fde 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,11 @@
   `getNextPageToken()` with `getNextToken()`, `getPreviousPageToken()` with `getPreviousToken()`, and add `getToken()`.
   These methods use new `PageToken` class (@vjik)
 - New #160: Add `Sort::hasFieldInConfig()` method that checks for the presence of a field in the sort config (@vjik)
+- New #161: Add `PageNotFoundException` (@vjik)
+- Chg #161: `PaginatorInterface::getCurrentPageSize()` returns 0 instead throws exception if page specified is 
+  not found (@vjik)
+- Enh #161: Add more specified psalm annotations to `CountableDataInterface::count()`,
+  `PaginatorInterface::getCurrentPageSize()` and `OffsetPaginator::getTotalItems()` (@vjik)
 
 ## 1.0.1 January 25, 2023
 
diff --git a/src/Paginator/OffsetPaginator.php b/src/Paginator/OffsetPaginator.php
index 97a595c0..85fe4933 100644
--- a/src/Paginator/OffsetPaginator.php
+++ b/src/Paginator/OffsetPaginator.php
@@ -46,6 +46,7 @@ final class OffsetPaginator implements PaginatorInterface
 
     /**
      * @var int Maximum number of items per page.
+     * @psalm-var positive-int
      */
     private int $pageSize = self::DEFAULT_PAGE_SIZE;
 
@@ -169,10 +170,11 @@ public function getCurrentPageSize(): int
         }
 
         if ($currentPage === $pages) {
+            /** @psalm-var positive-int Because total items is more than offset */
             return $this->getTotalItems() - $this->getOffset();
         }
 
-        throw new PaginatorException('Page not found.');
+        return 0;
     }
 
     /**
@@ -189,6 +191,8 @@ public function getOffset(): int
      * Get total number of items in the whole data reader being paginated.
      *
      * @return int Total items number.
+     *
+     * @psalm-return non-negative-int
      */
     public function getTotalItems(): int
     {
@@ -232,7 +236,7 @@ public function getSort(): ?Sort
     public function read(): iterable
     {
         if ($this->getCurrentPage() > $this->getInternalTotalPages()) {
-            throw new PaginatorException('Page not found.');
+            throw new PageNotFoundException();
         }
 
         yield from $this->dataReader
@@ -257,7 +261,7 @@ public function isOnFirstPage(): bool
     public function isOnLastPage(): bool
     {
         if ($this->getCurrentPage() > $this->getInternalTotalPages()) {
-            throw new PaginatorException('Page not found.');
+            throw new PageNotFoundException();
         }
 
         return $this->getCurrentPage() === $this->getInternalTotalPages();
@@ -268,6 +272,9 @@ public function isPaginationRequired(): bool
         return $this->getTotalPages() > 1;
     }
 
+    /**
+     * @psalm-return non-negative-int
+     */
     private function getInternalTotalPages(): int
     {
         return max(1, $this->getTotalPages());
diff --git a/src/Paginator/PageNotFoundException.php b/src/Paginator/PageNotFoundException.php
new file mode 100644
index 00000000..279967fb
--- /dev/null
+++ b/src/Paginator/PageNotFoundException.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Yiisoft\Data\Paginator;
+
+final class PageNotFoundException extends PaginatorException
+{
+    public function __construct()
+    {
+        parent::__construct('Page not found.');
+    }
+}
diff --git a/src/Paginator/PaginatorInterface.php b/src/Paginator/PaginatorInterface.php
index 65574fe1..eee45647 100644
--- a/src/Paginator/PaginatorInterface.php
+++ b/src/Paginator/PaginatorInterface.php
@@ -84,9 +84,9 @@ public function getPageSize(): int;
      *
      * @see getPageSize()
      *
-     * @throws PaginatorException If page specified is not found.
-     *
      * @return int Current page size.
+     *
+     * @psalm-return non-negative-int
      */
     public function getCurrentPageSize(): int;
 
@@ -116,7 +116,7 @@ public function getSort(): ?Sort;
     /**
      * Get iterator that could be used to read currently active page items.
      *
-     * @throws PaginatorException If page specified is not found.
+     * @throws PageNotFoundException If page specified is not found.
      *
      * @return iterable Iterator with items for the current page.
      * @psalm-return iterable<TKey, TValue>
@@ -126,7 +126,7 @@ public function read(): iterable;
     /**
      * Get whether current page is the last one.
      *
-     * @throws PaginatorException If page specified is not found.
+     * @throws PageNotFoundException If page specified is not found.
      *
      * @return bool Whether current page is the last one.
      */
diff --git a/src/Reader/CountableDataInterface.php b/src/Reader/CountableDataInterface.php
index 72335189..605d7602 100644
--- a/src/Reader/CountableDataInterface.php
+++ b/src/Reader/CountableDataInterface.php
@@ -13,6 +13,8 @@ interface CountableDataInterface extends Countable
 {
     /**
      * @return int Number of items in the data.
+     *
+     * @psalm-return non-negative-int
      */
     public function count(): int;
 }
diff --git a/tests/Paginator/OffsetPaginatorTest.php b/tests/Paginator/OffsetPaginatorTest.php
index 24a47f8c..6411d433 100644
--- a/tests/Paginator/OffsetPaginatorTest.php
+++ b/tests/Paginator/OffsetPaginatorTest.php
@@ -8,6 +8,7 @@
 use LogicException;
 use PHPUnit\Framework\Attributes\DataProvider;
 use Yiisoft\Data\Paginator\OffsetPaginator;
+use Yiisoft\Data\Paginator\PageNotFoundException;
 use Yiisoft\Data\Paginator\PageToken;
 use Yiisoft\Data\Paginator\PaginatorException;
 use Yiisoft\Data\Paginator\PaginatorInterface;
@@ -222,7 +223,7 @@ public function testReadCurrentPageCannotBeLargerThanMaxPages(): void
         ;
 
         $this->assertSame(3, $paginator->getTotalPages());
-        $this->expectException(PaginatorException::class);
+        $this->expectException(PageNotFoundException::class);
         $this->expectExceptionMessage('Page not found.');
 
         $this->iterableToArray($paginator->read());
@@ -397,7 +398,7 @@ public function testIsLastPageBeyondMaxPages(): void
         ;
 
         $this->assertSame(3, $paginator->getTotalPages());
-        $this->expectException(PaginatorException::class);
+        $this->expectException(PageNotFoundException::class);
         $this->expectExceptionMessage('Page not found.');
 
         $paginator->isOnLastPage();
@@ -446,14 +447,10 @@ public function testGetCurrentPageCannotBeLargerThanMaxPages(): void
         $dataReader = new IterableDataReader(self::DEFAULT_DATASET);
         $paginator = (new OffsetPaginator($dataReader))
             ->withPageSize(2)
-            ->withCurrentPage(4)
-        ;
+            ->withCurrentPage(4);
 
         $this->assertSame(5, $paginator->getTotalItems());
-        $this->expectException(PaginatorException::class);
-        $this->expectExceptionMessage('Page not found.');
-
-        $paginator->getCurrentPageSize();
+        $this->assertSame(0, $paginator->getCurrentPageSize());
     }
 
     public function testEmptyDataSet(): void