ForHosting KIT · Developer Utilities

Orthodox Easter date calculator

Eastern Orthodox Easter, also called Pascha, is the central movable feast of the Orthodox Christian year.

● BetaFree · in your browser

Use it from WebAPIEmailTelegramApp soon

Unlike Western Easter, which follows the Gregorian computus adopted after 1582, most Orthodox jurisdictions still determine the date of Pascha with the ancient Julian tables of the lunar epact and the Sunday after the full moon that falls on or after the Julian spring equinox. The resulting Julian March or April Sunday is then converted to the civil Gregorian calendar so that planners, schools, and apps can show a familiar ISO date. This calculator implements that exact pipeline for any integer year greater than or equal to one: pure modular arithmetic for the Julian computus, a century offset of floor of year over one hundred minus floor of year over four hundred minus two, and deterministic month and day carry without any wall-clock Date object. Known modern fixtures such as 2024 May 5, 2025 April 20, and 2026 April 12 are reproduced exactly, and invalid years below one are rejected with a clear validation error rather than a silent wrong answer.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

How do I use this capability?

Complete the fields above and run it on this page. The form highlights anything that needs attention.

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/date/easter-orthodox

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/date/easter-orthodox \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"year":2024}'

const res = await fetch("https://api.kit.forhosting.com/date/easter-orthodox", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "year": 2024
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/date/easter-orthodox",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "year": 2024
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/date/easter-orthodox", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"year":2024}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"year":2024}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/date/easter-orthodox", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "year": 2024
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "date.easter_orthodox",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Read the full KIT documentation →