Add an IVF & FET Due Date Calculator to Your Website

Updated August 13, 2026

Build Your IVF Due Date Calculator

Add this ivf & fet due date 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/ivf-due-date-calculator?accent=135f5e"
    title="IVF and frozen embryo transfer due date calculator"
    width="100%"
    height="500"
    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/ivf-due-date-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>

IVF & FET Due Date 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.

IVF & FET Due Date 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 500px high.

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

IVF & FET Due Date 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.

IVF & FET Due Date 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.

IVF & FET Due Date 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 IVF Due Date Estimate Is Calculated

The estimate treats fertilization as 266 days before the due date and subtracts the embryo's age at transfer. A day-3 transfer therefore adds 263 days to the transfer date, while a day-5 transfer adds 261 days. Those two formulas match the ART dating examples in ACOG's due-date guidance.

Fresh and frozen transfers use the same date arithmetic when total embryo age is known. For a frozen transfer, total age means the culture days before cryopreservation plus any culture days after warming. The fertility clinic's documented gestational age and due date always take priority over this informational estimate.

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 500px 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.

What embryo age should be used for a frozen transfer?

Use the total culture age: days before freezing plus days after warming, if any. The fertility clinic can confirm the correct value.