diff --git a/4dev/tests/CoreLibsConvertStringsTest.php b/4dev/tests/CoreLibsConvertStringsTest.php
index 7270ec2a..90415d20 100644
--- a/4dev/tests/CoreLibsConvertStringsTest.php
+++ b/4dev/tests/CoreLibsConvertStringsTest.php
@@ -49,6 +49,24 @@ final class CoreLibsConvertStringsTest extends TestCase
 				null,
 				'12-34'
 			],
+			'string format trailing match' => [
+				'1234',
+				'2-2-',
+				null,
+				'12-34'
+			],
+			'string format leading match' => [
+				'1234',
+				'-2-2',
+				null,
+				'12-34'
+			],
+			'string format double inside match' => [
+				'1234',
+				'2--2',
+				null,
+				'12--34',
+			],
 			'string format short first' => [
 				'1',
 				'2-2',
@@ -109,6 +127,12 @@ final class CoreLibsConvertStringsTest extends TestCase
 				null,
 				'あいうえ'
 			],
+			'mutltibyte split string' => [
+				'1234',
+				'２-２',
+				null,
+				'1234'
+			],
 		];
 	}
 
@@ -148,6 +172,90 @@ final class CoreLibsConvertStringsTest extends TestCase
 			$output
 		);
 	}
+
+	/**
+	 * Undocumented function
+	 *
+	 * @return array
+	 */
+	public function countSplitPartsProvider(): array
+	{
+		return [
+			'0 elements' => [
+				'',
+				null,
+				0
+			],
+			'1 element' => [
+				'1',
+				null,
+				1,
+			],
+			'2 elements, trailing' => [
+				'1-2-',
+				null,
+				2
+			],
+			'2 elements, leading' => [
+				'-1-2',
+				null,
+				2
+			],
+			'2 elements, midde double' => [
+				'1--2',
+				null,
+				2
+			],
+			'4 elements' => [
+				'1-2-3-4',
+				null,
+				4
+			],
+			'3 elemenst, other splitter' => [
+				'2-3_3',
+				'-_',
+				3
+			],
+			'illegal splitter' => [
+				'あsdf',
+				null,
+				0
+			]
+		];
+	}
+
+	/**
+	 * count split parts
+	 *
+	 * @covers ::countSplitParts
+	 * @dataProvider countSplitPartsProvider
+	 * @testdox countSplitParts $input with splitters $split_characters will be $expected [$_dataName]
+	 *
+	 * @param  string      $input
+	 * @param  string|null $split_characters
+	 * @param  int         $expected
+	 * @return void
+	 */
+	public function testCountSplitParts(
+		string $input,
+		?string $split_characters,
+		int $expected
+	): void {
+		if ($split_characters === null) {
+			$output = \CoreLibs\Convert\Strings::countSplitParts(
+				$input
+			);
+		} else {
+			$output = \CoreLibs\Convert\Strings::countSplitParts(
+				$input,
+				$split_characters
+			);
+		}
+		$this->assertEquals(
+			$expected,
+			$output
+		);
+	}
 }
 
 // __END__
diff --git a/www/admin/class_test.strings.php b/www/admin/class_test.strings.php
index 23b26075..ff3f6168 100644
--- a/www/admin/class_test.strings.php
+++ b/www/admin/class_test.strings.php
@@ -68,7 +68,15 @@ print "Convert: $string with $split to: "
 	. \CoreLibs\Convert\Strings::splitFormatString($string, $split)
 	. "<br>";
 
-
+$test_splits = [
+	'',
+	'2',
+	'2-2',
+	'2-3-4',
+];
+foreach ($test_splits as $split) {
+	print "$split with count: " . \CoreLibs\Convert\Strings::countSplitParts($split) . "<br>";
+}
 
 // error message
 print $log->printErrorMsg();
diff --git a/www/lib/CoreLibs/Convert/Strings.php b/www/lib/CoreLibs/Convert/Strings.php
index 09a99756..1627f234 100644
--- a/www/lib/CoreLibs/Convert/Strings.php
+++ b/www/lib/CoreLibs/Convert/Strings.php
@@ -10,6 +10,38 @@ namespace CoreLibs\Convert;
 
 class Strings
 {
+	/**
+	 * return the elements in the split list
+	 * 0 if nothing / invalid split
+	 * 1 if no split character found
+	 *
+	 * @param  string $split_format
+	 * @param  string $split_characters
+	 * @return int
+	 */
+	public static function countSplitParts(
+		string $split_format,
+		string $split_characters = '-'
+	): int {
+		if (
+			empty($split_format) ||
+			// non valid characters inside, abort
+			!preg_match("/^[0-9" . $split_characters . "]/", $split_format) ||
+			preg_match('/[^\x20-\x7e]/', $split_characters)
+		) {
+			return 0;
+		}
+		$split_list = preg_split(
+			// allowed split characters
+			"/([" . $split_characters . "]{1})/",
+			$split_format
+		);
+		if (!is_array($split_list)) {
+			return 0;
+		}
+		return count(array_filter($split_list));
+	}
+
 	/**
 	 * split format a string base on a split format string
 	 * split format string is eg
@@ -31,18 +63,19 @@ class Strings
 		string $split_format,
 		string $split_characters = '-'
 	): string {
-		// abort if split format is empty
-		if (empty($split_format)) {
+		if (
+			// abort if split format is empty
+			empty($split_format) ||
+			// if not in the valid ASCII character range for any of the strings
+			preg_match('/[^\x20-\x7e]/', $value) ||
+			// preg_match('/[^\x20-\x7e]/', $split_format) ||
+			preg_match('/[^\x20-\x7e]/', $split_characters) ||
+			// only numbers and split characters in split_format
+			!preg_match("/[0-9" . $split_characters . "]/", $split_format)
+		) {
 			return $value;
 		}
-		// if not in the valid ASCII character range
-		// might need some tweaking
-		if (preg_match('/[^\x20-\x7e]/', $value)) {
-			return $value;
-		}
-		// if (!mb_check_encoding($value, 'ASCII')) {
-		// 	return $value;
-		// }
+		// split format list
 		$split_list = preg_split(
 			// allowed split characters
 			"/([" . $split_characters . "]{1})/",
@@ -65,7 +98,7 @@ class Strings
 				}
 				$out .= $_part;
 				$pos += (int)$offset;
-			} else {
+			} elseif ($pos) { // if first, do not add
 				$out .= $offset;
 				$last_split = $offset;
 			}