diff --git a/application/LinkDB.php b/application/LinkDB.php
index 8ca0fab3..5e38e848 100644
--- a/application/LinkDB.php
+++ b/application/LinkDB.php
@@ -463,6 +463,39 @@ public function linksCountPerTag($filteringTags = [], $visibility = 'all')
         return $tags;
     }
 
+    /**
+     * Rename or delete a tag across all links.
+     *
+     * @param string $from Tag to rename
+     * @param string $to   New tag. If none is provided, the from tag will be deleted
+     *
+     * @return array|bool List of altered links or false on error
+     */
+    public function renameTag($from, $to)
+    {
+        if (empty($from)) {
+            return false;
+        }
+        $delete = empty($to);
+        // True for case-sensitive tag search.
+        $linksToAlter = $this->filterSearch(['searchtags' => $from], true);
+        foreach($linksToAlter as $key => &$value)
+        {
+            $tags = preg_split('/\s+/', trim($value['tags']));
+            if (($pos = array_search($from, $tags)) !== false) {
+                if ($delete) {
+                    unset($tags[$pos]); // Remove tag.
+                } else {
+                    $tags[$pos] = trim($to);
+                }
+                $value['tags'] = trim(implode(' ', array_unique($tags)));
+                $this[$value['id']] = $value;
+            }
+        }
+
+        return $linksToAlter;
+    }
+
     /**
      * Returns the list of days containing articles (oldest first)
      * Output: An array containing days (in format YYYYMMDD).
diff --git a/index.php b/index.php
index eb6b17d9..891a2ece 100644
--- a/index.php
+++ b/index.php
@@ -685,6 +685,7 @@ function showLinkList($PAGE, $LINKSDB, $conf, $pluginManager) {
  * @param ConfigManager $conf          Configuration Manager instance.
  * @param PluginManager $pluginManager Plugin Manager instance,
  * @param LinkDB        $LINKSDB
+ * @param History       $history       instance
  */
 function renderPage($conf, $pluginManager, $LINKSDB, $history)
 {
@@ -1176,39 +1177,16 @@ function renderPage($conf, $pluginManager, $LINKSDB, $history)
             die('Wrong token.');
         }
 
-        if (isset($_POST['deletetag']) && !empty($_POST['fromtag'])) {
-            $delete = true;
-        } else if (isset($_POST['renametag']) && !empty($_POST['fromtag']) && !empty($_POST['totag'])) {
-            $delete = false;
-        } else {
-            $PAGE->renderPage('changetag');
-            exit;
-        }
-
-        $count = 0;
-        $needle = trim($_POST['fromtag']);
-        // True for case-sensitive tag search.
-        $linksToAlter = $LINKSDB->filterSearch(array('searchtags' => $needle), true);
-        foreach($linksToAlter as $key => $value)
-        {
-            $tags = explode(' ',trim($value['tags']));
-            if (($pos = array_search($needle,$tags)) !== false) {
-                if ($delete) {
-                    unset($tags[$pos]); // Remove tag.
-                } else {
-                    $tags[$pos] = trim($_POST['totag']);
-                }
-                $value['tags'] = trim(implode(' ', array_unique($tags)));
-                $LINKSDB[$key]=$value;
-                $history->updateLink($LINKSDB[$key]);
-                ++$count;
-            }
-        }
+        $alteredLinks = $LINKSDB->renameTag(escape($_POST['fromtag']), escape($_POST['totag']));
         $LINKSDB->save($conf->get('resource.page_cache'));
+        foreach ($alteredLinks as $link) {
+            $history->updateLink($link);
+        }
+        $delete = empty($_POST['totag']);
         $redirect = $delete ? 'do=changetag' : 'searchtags='. urlencode(escape($_POST['totag']));
         $alert = $delete
-            ? sprintf(t('The tag was removed from %d links.'), $count)
-            : sprintf(t('The tag was renamed in %d links.'), $count);
+            ? sprintf(t('The tag was removed from %d links.'), count($alteredLinks))
+            : sprintf(t('The tag was renamed in %d links.'), count($alteredLinks));
         echo '<script>alert("'. $alert .'");document.location=\'?'. $redirect .'\';</script>';
         exit;
     }
@@ -2237,6 +2215,12 @@ function resizeImage($filepath)
     $_SESSION['LINKS_PER_PAGE'] = $conf->get('general.links_per_page', 20);
 }
 
+try {
+    $history = new History($conf->get('resource.history'));
+} catch(Exception $e) {
+    die($e->getMessage());
+}
+
 $linkDb = new LinkDB(
     $conf->get('resource.datastore'),
     isLoggedIn(),
@@ -2245,12 +2229,6 @@ function resizeImage($filepath)
     $conf->get('redirector.encode_url')
 );
 
-try {
-    $history = new History($conf->get('resource.history'));
-} catch(Exception $e) {
-    die($e->getMessage());
-}
-
 $container = new \Slim\Container();
 $container['conf'] = $conf;
 $container['plugins'] = $pluginManager;
diff --git a/tests/LinkDBTest.php b/tests/LinkDBTest.php
index 25438277..5b2f3667 100644
--- a/tests/LinkDBTest.php
+++ b/tests/LinkDBTest.php
@@ -487,4 +487,59 @@ public function testReorderLinksDesc()
             $this->assertEquals($linkIds[$cpt++], $key);
         }
     }
+
+    /**
+     * Test rename tag with a valid value present in multiple links
+     */
+    public function testRenameTagMultiple()
+    {
+        self::$refDB->write(self::$testDatastore);
+        $linkDB = new LinkDB(self::$testDatastore, true, false);
+
+        $res = $linkDB->renameTag('cartoon', 'Taz');
+        $this->assertEquals(3, count($res));
+        $this->assertContains(' Taz ', $linkDB[4]['tags']);
+        $this->assertContains(' Taz ', $linkDB[1]['tags']);
+        $this->assertContains(' Taz ', $linkDB[0]['tags']);
+    }
+
+    /**
+     * Test rename tag with a valid value
+     */
+    public function testRenameTagCaseSensitive()
+    {
+        self::$refDB->write(self::$testDatastore);
+        $linkDB = new LinkDB(self::$testDatastore, true, false, '');
+
+        $res = $linkDB->renameTag('sTuff', 'Taz');
+        $this->assertEquals(1, count($res));
+        $this->assertEquals('Taz', $linkDB[41]['tags']);
+    }
+
+    /**
+     * Test rename tag with invalid values
+     */
+    public function testRenameTagInvalid()
+    {
+        $linkDB = new LinkDB(self::$testDatastore, false, false);
+
+        $this->assertFalse($linkDB->renameTag('', 'test'));
+        $this->assertFalse($linkDB->renameTag('', ''));
+        // tag non existent
+        $this->assertEquals([], $linkDB->renameTag('test', ''));
+        $this->assertEquals([], $linkDB->renameTag('test', 'retest'));
+    }
+
+    /**
+     * Test delete tag with a valid value
+     */
+    public function testDeleteTag()
+    {
+        self::$refDB->write(self::$testDatastore);
+        $linkDB = new LinkDB(self::$testDatastore, true, false);
+
+        $res = $linkDB->renameTag('cartoon', null);
+        $this->assertEquals(3, count($res));
+        $this->assertNotContains('cartoon', $linkDB[4]['tags']);
+    }
 }