ForHosting KIT · Developer Utilities

IVF transfer due date calculator

After an IVF embryo transfer, patients and clinics need a transparent estimated due date that starts from the transfer day and the embryo’s age, not from a last menstrual period that may not exist in a medicated cycle.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

This IVF transfer due date calculator accepts a strict YYYY-MM-DD transfer date and an integer embryo age in days (zero through seven), applies the standard clinical formula EDD equals transfer date plus two hundred sixty-six minus embryo age days, and returns the due date, days added, gestational age at transfer, a short step list, and the formula string. There is no wall clock, no timezone shift, and no random seed: the same transfer date and embryo age always yield the same due date in the free browser widget and on the prepaid API path. When transfer_date or embryo_age_days is missing or invalid, the task fails with invalid_input instead of inventing a date. Use it for fertility-clinic intake, patient education after day-three or day-five transfer, and automation that needs a reproducible IVF dating baseline before ultrasound refines the plan.

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/health/ivf-due-date

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/health/ivf-due-date \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"transfer_date":"2026-03-15","embryo_age_days":5}'

const res = await fetch("https://api.kit.forhosting.com/health/ivf-due-date", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "transfer_date": "2026-03-15",
    "embryo_age_days": 5
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/health/ivf-due-date",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "transfer_date": "2026-03-15",
    "embryo_age_days": 5
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/ivf-due-date", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"transfer_date":"2026-03-15","embryo_age_days":5}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"transfer_date":"2026-03-15","embryo_age_days":5}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/ivf-due-date", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "transfer_date": "2026-03-15",
  "embryo_age_days": 5
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "health.ivf_due_date",
  "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 →