Add an hCG Doubling-Time Calculator to Your Website

Updated August 13, 2026

Build Your hCG Doubling-Time Calculator

Add this hcg doubling-time calculator to your website without building, hosting, or maintaining it yourself. The same embed works on WordPress, Wix, Squarespace, Webflow, and any HTML website.

This free tool is provided by Pregnancy Safe, which helps expecting parents track their pregnancy and check the safety of thousands of products and categories.

Choose an accent color, preview the calculator, and copy the embed code.

Customize the widget

Live preview

Copy the embed code

Paste this complete snippet into your website's HTML or embed block.

<div style="max-width:640px">
  <iframe
    src="https://pregnancysafeapp.com/embed/hcg-doubling-calculator?accent=135f5e"
    title="hCG doubling-time calculator"
    width="100%"
    height="790"
    loading="lazy"
    style="display:block;border:0;width:100%"
    referrerpolicy="strict-origin-when-cross-origin"
  ></iframe>
  <script>
    (() => {
      const iframe = document.currentScript.previousElementSibling;
      if (!(iframe instanceof HTMLIFrameElement)) return;
      window.addEventListener("message", (event) => {
        if (event.source !== iframe.contentWindow || event.origin !== "https://pregnancysafeapp.com") return;
        if (event.data?.type !== "pregnancy-safe-widget:resize") return;
        const height = Number(event.data.height);
        if (!Number.isFinite(height) || height < 200 || height > 1400) return;
        iframe.height = String(Math.ceil(height));
      });
    })();
  </script>
  <p style="margin:8px 0 0;display:flex;align-items:center;justify-content:center;gap:4px;font:12px/18px Arial,sans-serif;color:#6b7280">
    Powered by
    <a href="https://pregnancysafeapp.com/widgets/hcg-doubling-calculator" target="_blank" rel="noopener" style="display:inline-flex;align-items:center;gap:4px;line-height:18px;color:#135f5e;font-weight:600;text-decoration:none">
      <img src="https://pregnancysafeapp.com/icon.webp" alt="" width="18" height="18" style="display:block;width:18px;height:18px;flex:0 0 18px;border:0" />
      Pregnancy Safe
    </a>
  </p>
</div>

hCG Doubling-Time Calculator for WordPress

Edit the page where you want the calculator.
Add a Custom HTML block by searching for HTML or typing /html.
Paste the complete embed code, preview the page, and publish.

WordPress may remove iframes for users without permission to publish unfiltered HTML. If the calculator disappears after saving, ask a site administrator to add the block. Elementor or Divi users can paste the same snippet into the builder's HTML/code module. See the official Custom HTML block guide.

hCG Doubling-Time Calculator for Wix

In the Wix Editor, choose Add Elements → Embed Code → Embed HTML.
Select Enter Code, paste the complete snippet, and click Apply.
Stretch the Wix embed element to the full column width and at least 790px high.

Wix only displays HTTPS embeds and does not automatically make its embed container responsive. See Wix's official widget embed guide.

hCG Doubling-Time Calculator for Squarespace

Edit the page and add a Code block where the calculator should appear.
Choose HTML, paste the complete snippet, and save the page.
Check the published page on mobile and desktop.

Squarespace supports iframe code in advanced Code blocks on eligible paid plans. If it does not appear while you are logged in, check the public page in a private window. See Squarespace's official custom-code guide.

hCG Doubling-Time Calculator for Webflow

Add a Code Embed element to the page.
Paste the complete snippet, then save and close the code editor.
Publish the site and verify the calculator at narrow and wide widths.

A suitable Workspace or active Site plan is required for Code Embed. See Webflow's official Code Embed guide.

hCG Doubling-Time Calculator HTML and iframe code

Paste the complete snippet into your page's HTML where the calculator should appear. Keep the iframe at width="100%" and the height generated by the builder. If your site uses a Content Security Policy, allow frames from https://pregnancysafeapp.com.

How the hCG Change Is Calculated

The calculator divides the second quantitative serum hCG value by the first. It reports the observed percentage change, applies a log-linear growth assumption to estimate an equivalent 48-hour change, and uses natural logarithms to estimate doubling time for rising values or halving time for falling values. This is mathematical interpolation or extrapolation—not a model of an individual pregnancy.

The familiar name of the tool does not mean hCG must double every 48 hours. In a study of 285 symptomatic pregnancies of unknown location that ultimately became viable intrauterine pregnancies, the predicted two-day minimal rise varied with the initial value: 49% below 1,500, 40% from 1,500–3,000, and 33% above 3,000 mIU/mL. Those findings describe a study population and are not safe standalone diagnostic cutoffs, so this widget deliberately does not compare a result with them or issue a normal, abnormal, viable, nonviable, or ectopic verdict.

ACOG states that one hCG result or one ultrasound may be insufficient and that serial hCG plus ultrasound may be needed when pregnancy location is uncertain. NICE advises that, in a pregnancy of unknown location, symptoms take priority over hCG and serial tests used for management should be as close as possible to 48 hours apart. Results must be interpreted with symptoms, gestational timing, ultrasound, and the laboratory method. Values entered into the widget remain in the visitor's browser.

Clinical and technical references:

Common Installation Questions

Do I need a WordPress plugin?

No. Paste the generated iframe snippet into a Custom HTML block. The same hosted widget works without installing or maintaining a plugin.

Why is the bottom of the widget cut off?

The complete generated snippet automatically resizes the calculator as it switches between the form and results. If a website builder removes the resize script, set its embed container to at least 790px high so the result and medical notes remain visible at narrow widths.

Does Pregnancy Safe receive the information a visitor enters?

No. The tool runs inside the visitor's browser. Pregnancy Safe does not send, store, log, or analyze the information entered into this widget.

Can this calculator diagnose a viable or ectopic pregnancy?

No. The output is mathematical only and cannot diagnose pregnancy location or outcome.

Should hCG always double every 48 hours?

No. Rates vary with the starting value and clinical circumstances. A clinician should interpret serial values together with symptoms and ultrasound.