diff --git a/ext/intl/dateformat/dateformat.stub.php b/ext/intl/dateformat/dateformat.stub.php
index 06f26b0658739..7582af2717fbe 100644
--- a/ext/intl/dateformat/dateformat.stub.php
+++ b/ext/intl/dateformat/dateformat.stub.php
@@ -159,6 +159,11 @@ public static function formatObject($datetime, $format = null, ?string $locale =
      */
     public function parse(string $string, &$offset = null): int|float|false {}
 
+    /**
+     * @param int $offset
+     */
+    public function parseToCalendar(string $string, &$offset = null): int|float|false {}
+
     /**
      * @param int $offset
      * @return array<string, int>|false
diff --git a/ext/intl/dateformat/dateformat_arginfo.h b/ext/intl/dateformat/dateformat_arginfo.h
index 4d16a26ef1673..df1de7d6895f4 100644
--- a/ext/intl/dateformat/dateformat_arginfo.h
+++ b/ext/intl/dateformat/dateformat_arginfo.h
@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 91f1dbe4843fd1d4dff7266e814a3c8f9aed882a */
+ * Stub hash: 56b66b1b51220ddbff698ec4c9a6ae60f3e0bfb0 */
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_class_IntlDateFormatter___construct, 0, 0, 1)
 	ZEND_ARG_TYPE_INFO(0, locale, IS_STRING, 1)
@@ -75,6 +75,11 @@ ZEND_BEGIN_ARG_WITH_TENTATIVE_RETURN_TYPE_MASK_EX(arginfo_class_IntlDateFormatte
 	ZEND_ARG_INFO_WITH_DEFAULT_VALUE(1, offset, "null")
 ZEND_END_ARG_INFO()
 
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_MASK_EX(arginfo_class_IntlDateFormatter_parseToCalendar, 0, 1, MAY_BE_LONG|MAY_BE_DOUBLE|MAY_BE_FALSE)
+	ZEND_ARG_TYPE_INFO(0, string, IS_STRING, 0)
+	ZEND_ARG_INFO_WITH_DEFAULT_VALUE(1, offset, "null")
+ZEND_END_ARG_INFO()
+
 ZEND_BEGIN_ARG_WITH_TENTATIVE_RETURN_TYPE_MASK_EX(arginfo_class_IntlDateFormatter_localtime, 0, 1, MAY_BE_ARRAY|MAY_BE_FALSE)
 	ZEND_ARG_TYPE_INFO(0, string, IS_STRING, 0)
 	ZEND_ARG_INFO_WITH_DEFAULT_VALUE(1, offset, "null")
@@ -104,6 +109,7 @@ ZEND_FUNCTION(datefmt_is_lenient);
 ZEND_FUNCTION(datefmt_format);
 ZEND_FUNCTION(datefmt_format_object);
 ZEND_FUNCTION(datefmt_parse);
+ZEND_METHOD(IntlDateFormatter, parseToCalendar);
 ZEND_FUNCTION(datefmt_localtime);
 ZEND_FUNCTION(datefmt_get_error_code);
 ZEND_FUNCTION(datefmt_get_error_message);
@@ -127,6 +133,7 @@ static const zend_function_entry class_IntlDateFormatter_methods[] = {
 	ZEND_RAW_FENTRY("format", zif_datefmt_format, arginfo_class_IntlDateFormatter_format, ZEND_ACC_PUBLIC, NULL, NULL)
 	ZEND_RAW_FENTRY("formatObject", zif_datefmt_format_object, arginfo_class_IntlDateFormatter_formatObject, ZEND_ACC_PUBLIC|ZEND_ACC_STATIC, NULL, NULL)
 	ZEND_RAW_FENTRY("parse", zif_datefmt_parse, arginfo_class_IntlDateFormatter_parse, ZEND_ACC_PUBLIC, NULL, NULL)
+	ZEND_ME(IntlDateFormatter, parseToCalendar, arginfo_class_IntlDateFormatter_parseToCalendar, ZEND_ACC_PUBLIC)
 	ZEND_RAW_FENTRY("localtime", zif_datefmt_localtime, arginfo_class_IntlDateFormatter_localtime, ZEND_ACC_PUBLIC, NULL, NULL)
 	ZEND_RAW_FENTRY("getErrorCode", zif_datefmt_get_error_code, arginfo_class_IntlDateFormatter_getErrorCode, ZEND_ACC_PUBLIC, NULL, NULL)
 	ZEND_RAW_FENTRY("getErrorMessage", zif_datefmt_get_error_message, arginfo_class_IntlDateFormatter_getErrorMessage, ZEND_ACC_PUBLIC, NULL, NULL)
diff --git a/ext/intl/dateformat/dateformat_parse.c b/ext/intl/dateformat/dateformat_parse.c
index 69aeff886d3b9..82b5a71bbee8f 100644
--- a/ext/intl/dateformat/dateformat_parse.c
+++ b/ext/intl/dateformat/dateformat_parse.c
@@ -31,7 +31,7 @@
  *	if set to 1 - store any error encountered  in the parameter parse_error
  *	if set to 0 - no need to store any error encountered  in the parameter parse_error
 */
-static void internal_parse_to_timestamp(IntlDateFormatter_object *dfo, char* text_to_parse, size_t text_len, int32_t *parse_pos, zval *return_value)
+static void internal_parse_to_timestamp(IntlDateFormatter_object *dfo, char* text_to_parse, size_t text_len, int32_t *parse_pos, bool update_calendar, zval *return_value)
 {
 	double	result =  0;
 	UDate 	timestamp   =0;
@@ -42,13 +42,22 @@ static void internal_parse_to_timestamp(IntlDateFormatter_object *dfo, char* tex
 	intl_convert_utf8_to_utf16(&text_utf16, &text_utf16_len, text_to_parse, text_len, &INTL_DATA_ERROR_CODE(dfo));
 	INTL_METHOD_CHECK_STATUS(dfo, "Error converting timezone to UTF-16" );
 
-	timestamp = udat_parse( DATE_FORMAT_OBJECT(dfo), text_utf16, text_utf16_len, parse_pos, &INTL_DATA_ERROR_CODE(dfo));
-	if( text_utf16 ){
-		efree(text_utf16);
+	if (UNEXPECTED(update_calendar)) {
+		UCalendar *parsed_calendar = (UCalendar *)udat_getCalendar(DATE_FORMAT_OBJECT(dfo));
+		udat_parseCalendar(DATE_FORMAT_OBJECT(dfo), parsed_calendar, text_utf16, text_utf16_len, parse_pos, &INTL_DATA_ERROR_CODE(dfo));
+		if (text_utf16) {
+			efree(text_utf16);
+		}
+		INTL_METHOD_CHECK_STATUS( dfo, "Calendar parsing failed" );
+		timestamp = ucal_getMillis( parsed_calendar, &INTL_DATA_ERROR_CODE(dfo));
+	} else {
+		timestamp = udat_parse(DATE_FORMAT_OBJECT(dfo), text_utf16, text_utf16_len, parse_pos, &INTL_DATA_ERROR_CODE(dfo));
+		if (text_utf16) {
+			efree(text_utf16);
+		}
 	}
 
 	INTL_METHOD_CHECK_STATUS( dfo, "Date parsing failed" );
-
 	/* Since return is in  sec. */
 	result = (double)timestamp / U_MILLIS_PER_SECOND;
 	if (result > (double)LONG_MAX || result < (double)LONG_MIN) {
@@ -145,18 +154,63 @@ PHP_FUNCTION(datefmt_parse)
 			RETURN_FALSE;
 		}
 		parse_pos = (int32_t)long_parse_pos;
-		if((size_t)parse_pos > text_len) {
+		if ((size_t)parse_pos > text_len) {
 			RETURN_FALSE;
 		}
 	}
-	internal_parse_to_timestamp( dfo, text_to_parse, text_len, z_parse_pos?&parse_pos:NULL, return_value);
-	if(z_parse_pos) {
+	internal_parse_to_timestamp( dfo, text_to_parse, text_len, z_parse_pos ? &parse_pos : NULL, false, return_value);
+	if (z_parse_pos) {
 		zval_ptr_dtor(z_parse_pos);
 		ZVAL_LONG(z_parse_pos, parse_pos);
 	}
 }
 /* }}} */
 
+PHP_METHOD(IntlDateFormatter, parseToCalendar)
+{
+	zend_string *text_to_parse = NULL;
+	zval* z_parse_pos = NULL;
+	int32_t parse_pos = -1;
+
+	DATE_FORMAT_METHOD_INIT_VARS;
+
+	ZEND_PARSE_PARAMETERS_START(1, 2)
+		Z_PARAM_STR(text_to_parse)
+		Z_PARAM_OPTIONAL
+		Z_PARAM_ZVAL(z_parse_pos)
+	ZEND_PARSE_PARAMETERS_END();
+
+	object = ZEND_THIS;
+
+	/* Fetch the object. */
+	DATE_FORMAT_METHOD_FETCH_OBJECT;
+
+	if (z_parse_pos) {
+		zend_long long_parse_pos;
+		ZVAL_DEREF(z_parse_pos);
+		bool failed = false;
+		long_parse_pos = zval_try_get_long(z_parse_pos, &failed);
+		if (failed) {
+			zend_argument_type_error(2, "must be of type int, %s given", zend_zval_value_name(z_parse_pos));
+			RETURN_THROWS();
+		}
+		if (ZEND_LONG_INT_OVFL(long_parse_pos)) {
+			intl_error_set_code(NULL, U_ILLEGAL_ARGUMENT_ERROR);
+			intl_error_set_custom_msg(NULL, "String index is out of valid range.", 0);
+			RETURN_FALSE;
+		}
+		parse_pos = (int32_t)long_parse_pos;
+		if (parse_pos != -1 && (size_t)parse_pos > ZSTR_LEN(text_to_parse)) {
+			RETURN_FALSE;
+		}
+	}
+	internal_parse_to_timestamp( dfo, ZSTR_VAL(text_to_parse), ZSTR_LEN(text_to_parse), z_parse_pos ? &parse_pos : NULL, true, return_value);
+	if (z_parse_pos) {
+		zval_ptr_dtor(z_parse_pos);
+		ZVAL_LONG(z_parse_pos, parse_pos);
+	}
+}
+
 /* {{{ Parse the string $value to a localtime array */
 PHP_FUNCTION(datefmt_localtime)
 {
diff --git a/ext/intl/tests/gh13766.phpt b/ext/intl/tests/gh13766.phpt
new file mode 100644
index 0000000000000..b01b557e497a6
--- /dev/null
+++ b/ext/intl/tests/gh13766.phpt
@@ -0,0 +1,35 @@
+--TEST--
+IntlDateFormatter::parse update its calendar
+--EXTENSIONS--
+intl
+--FILE--
+<?php
+$oIntlDateFormatter = new IntlDateFormatter("en_GB");
+$oIntlDateFormatter->setTimeZone('Europe/Berlin');
+$oIntlDateFormatter->setPattern('VV');
+
+var_dump($oIntlDateFormatter->parse('America/Los_Angeles', $offset1));
+var_dump($oIntlDateFormatter->getTimeZone()->getID());
+var_dump($oIntlDateFormatter->parseToCalendar('America/Los_Angeles', $offset2));
+var_dump($oIntlDateFormatter->getTimeZone()->getID());
+$offset3 = "offset";
+
+try {
+	$oIntlDateFormatter->parseToCalendar('America/Los_Angeles', $offset3);
+} catch (\TypeError $e) {
+	echo $e->getMessage() . PHP_EOL;
+}
+$offset3 = PHP_INT_MAX * 16;
+try {
+	$oIntlDateFormatter->parseToCalendar('America/Los_Angeles', $offset3);
+} catch (\ValueError $e) {
+	echo $e->getMessage();
+}
+--EXPECTF--
+int(%d)
+string(13) "Europe/Berlin"
+int(%d)
+string(19) "America/Los_Angeles"
+IntlDateFormatter::parseToCalendar(): Argument #2 ($offset) must be of type int, string given
+
+Deprecated: Implicit conversion from float 1.4757395258967641E+20 to int loses precision in %s on line %d