ForHosting KIT · Developer Utilities

Pregnancy test calculator

A quantitative pregnancy test is more than a plus or minus on a stick: the same blood or urine hCG reading means different things on day four after ovulation than it does on day fourteen.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

This pregnancy test calculator accepts days since ovulation and an hCG concentration in milli-international units per millilitre, then returns an estimated pregnancy probability as a percentage together with the hormone class (below threshold, grey zone, or positive), an implantation-timing factor, and a short interpretation. Negative days since ovulation are rejected as invalid_input rather than silently clipped, because a clock that runs backwards is not a test result. The model is a documented, deterministic Bayes update—not a clinic, not a lab, and not medical advice—so education sites, fertility-tracking apps, and coding fixtures can all call the same pure function in the browser for free or via the API at $0.002 per successful request.

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

What does this pregnancy test calculator need as input?

Two finite numbers: days since ovulation (zero or more) and quantitative hCG in mIU/mL (zero or more). It returns an estimated pregnancy probability as a percentage.

What happens if days since ovulation is negative?

The task fails with invalid_input. A negative day count is not a real elapsed time and is never billed.

Is a high percentage a medical diagnosis of pregnancy?

No. The figure is an educational posterior from a published analytic model. Confirm with a licensed clinician and, when indicated, serial quantitative hCG or ultrasound.

Why can a positive-looking hCG still score as indeterminate before day seven?

Endogenous hCG from a new pregnancy is not expected that early. Elevated readings in that window are mixed toward the prior because residual or exogenous hormone (for example a trigger shot) is a common alternative.

What does the pregnancy test calculator cost?

The browser tool is free and runs locally. API calls use prepaid KIT balance at $0.002 per successful request; failed tasks are never charged.

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/pregnancy-test

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/pregnancy-test \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"days_since_ovulation":14,"hcg":150}'

const res = await fetch("https://api.kit.forhosting.com/health/pregnancy-test", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "days_since_ovulation": 14,
    "hcg": 150
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/health/pregnancy-test",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "days_since_ovulation": 14,
    "hcg": 150
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/pregnancy-test", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"days_since_ovulation":14,"hcg":150}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"days_since_ovulation":14,"hcg":150}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/pregnancy-test", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "days_since_ovulation": 14,
  "hcg": 150
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "health.pregnancy_test",
  "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.

Limits

`min_days_since_ovulation`	0
`min_hcg`	0

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 →