UCP v1.1.3 Standard Released

One Timestamp.
Seven Calendars.

Name: Unified Calendar Protocol (UCP)
Author: Yuanyu (元宇)

The Unified Calendar Protocol (UCP) is an open standard that harmonizes the Gregorian solar grid with the pure astrophysics of Chinese, Indian, Islamic, and Buddhist timekeeping.

Try the Converter View Core on GitHub

Anatomy of a UCP String

Machine-readable, human-parseable, and timezone-proof. The UCP string natively embeds multiple cultural calendars into a single logical format.

UE-12024::05.23-08::04.16.18 H11.15 [Bing-Chen]T14:30:45Z

1. The Anchor

Anchored to the Universal Epoch (Holocene) to prevent "Year Zero" religious bias.

2. Solar Track

Month.Day-SolarTerm. Merges the Gregorian grid with Chinese solar astrophysics (Jieqi).

3. Lunar & Hijri Track

Embeds Indian Tithis, Chinese Pillars, and the Islamic Umm al-Qura (H) algorithmic calendar.

4. Absolute Time

Strictly locked to UTC (Geocentric) to prevent intercalation and Timezone drift globally.

Live Engine PreviewPowered by @unified-calendar/core

Testing the open-source Node.js library directly in the browser.

UCP Interactive Decoder

Select Date & Time (UTC)

Engine Status

Library Loaded

UTC Lock Active

$ ucp-cli decode --date="2026-03-21T14:30:00Z"

Generated UCP Protocol String

UE-12026 :: 03.21-04 :: 02.03.03 H10.02 [Jia-Wu] T14:30:00Z

--- Decoded Cultural Data (7 Systems) ---

[Gregorian]Year 2026, Month 3, Day 21[Xia (Hsia)]Year Bing-Wu (丙午), Month Xin-Mao (辛卯), Day Jia-Wu (甲午) (Term: 春分 / Spring Equinox)[Chinese Trad.]Year 4724, M: 2, D: 3[Hindu Lunisolar]Amanta Month 1, Tithi 3, Nakshatra 3[Buddhist Era]Year BE 2569, Lunar Month 2, Day 3 [Saka Samvat]Year Saka 1947, Month 12, Day 30[Hijri]Year 1447 AH, Shawwal (M: 10), Day 2

Ending Intercalation Drift.

Because Chinese leap months (Zhongqi), Indian leap months (Adhika Masa), and the Islamic Hilal are calculated using completely different astronomical triggers, mapping them mathematically creates endless bugs and cultural erasure. UCP fixes this at the mathematical root.

Gregorian

Holocene Epoch & Solar Grid

Xia (Hsia)

24 Solar Terms & Stem-Branches

Chinese

Traditional Lunisolar Calendar

Hindu

Amanta Transits & Vedic Tithis

Buddhist

Observational Uposatha Phases

Saka Samvat

Indian National Civil Calendar

Hijri

Umm al-Qura Algorithmic Phase

Built for Developers

Add UCP support to your backend in minutes. The open-source Node.js engine abstracts away the complex astrophysics, allowing you to generate UCP components instantly.

$ npm install @unified-calendar/core

import { decodeUCP } from '@unified-calendar/core';

const data = decodeUCP('2026-03-21T14:30Z');

Read the Docs on GitHub

Launching Soon

Enterprise Cloud API

Maintained by Yuanyu (元宇), the upcoming enterprise REST API will provide high-precision global holiday data, eclipse tracking, and guaranteed SLAs for international HR and scheduling platforms.