---
title: Datetime parsing and formatting
description: Datetime parsing is a switch from a string datetime to a complex datetime, and datetime formatting is a switch from a complex datetime to a string datetime...
url: https://www.elastic.co/elastic/docs-builder/docs/3028/reference/scripting-languages/painless/painless-datetime-parsing-and-formatting
products:
  - Elasticsearch
  - Painless
applies_to:
  - Elastic Cloud Serverless: Generally available
  - Elastic Stack: Generally available
---

# Datetime parsing and formatting
Datetime parsing is a switch from a string datetime to a complex datetime, and datetime formatting is a switch from a complex datetime to a string datetime.
A [DateTimeFormatter](https://www.elastic.co/guide/en/elasticsearch/painless/current/painless-api-reference-shared-java-time-format.html#painless-api-reference-shared-DateTimeFormatter) is a complex type ([object](/elastic/docs-builder/docs/3028/reference/scripting-languages/painless/painless-types#reference-types)) that defines the allowed sequence of characters for a string datetime. Datetime parsing and formatting often require a DateTimeFormatter. For more information about how to use a DateTimeFormatter see the [Java documentation](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/format/DateTimeFormatter.html).

## Datetime parsing examples

- Parse from milliseconds:
  ```java
  String milliSinceEpochString = "434931330000";
  long milliSinceEpoch = Long.parseLong(milliSinceEpochString);
  Instant instant = Instant.ofEpochMilli(milliSinceEpoch);
  ZonedDateTime zdt = ZonedDateTime.ofInstant(instant, ZoneId.of('Z'));
  ```
- Parse from ISO 8601:
  ```java
  String datetime = '1983-10-13T22:15:30Z';
  ZonedDateTime zdt = ZonedDateTime.parse(datetime); 
  ```
- Parse from RFC 1123:
  ```java
  String datetime = 'Thu, 13 Oct 1983 22:15:30 GMT';
  ZonedDateTime zdt = ZonedDateTime.parse(datetime,
          DateTimeFormatter.RFC_1123_DATE_TIME); 
  ```
- Parse from a custom format:
  ```java
  String datetime = 'custom y 1983 m 10 d 13 22:15:30 Z';
  DateTimeFormatter dtf = DateTimeFormatter.ofPattern(
          "'custom' 'y' yyyy 'm' MM 'd' dd HH:mm:ss VV");
  ZonedDateTime zdt = ZonedDateTime.parse(datetime, dtf); 
  ```


## Datetime formatting examples

- Format to ISO 8601:
  ```java
  ZonedDateTime zdt =
          ZonedDateTime.of(1983, 10, 13, 22, 15, 30, 0, ZoneId.of('Z'));
  String datetime = zdt.format(DateTimeFormatter.ISO_INSTANT); 
  ```
- Format to a custom format:
  ```java
  ZonedDateTime zdt =
          ZonedDateTime.of(1983, 10, 13, 22, 15, 30, 0, ZoneId.of('Z'));
  DateTimeFormatter dtf = DateTimeFormatter.ofPattern(
          "'date:' yyyy/MM/dd 'time:' HH:mm:ss");
  String datetime = zdt.format(dtf); 
  ```