Free Natal Chart Calculator for Your Website (Pay Only for the Charts People Make)

"Free natal chart calculator for my website" usually ends in one of three places: a WordPress plugin last updated years ago, an iframe of someone else's chart site with their logo on it, or a quote from a developer. None of those is free once you count your time, and two of them hand your visitor to somebody else.

This one is free in the plain sense: any OpenEphemeris account, including the free tier, can put a natal chart calculator on its own site with lead capture. The only thing you pay for is the charts your visitors actually generate, and there is no subscription unless you want one.

What "free" means here, exactly

Creating the widget	Free, on every account, no card
Loading it on your page, the place search, lead submissions	Free
Each natal chart a visitor generates	3 credits
Credits a new account starts with	150 (50 charts)
Topping up	$5 → 150 · $10 → 350 · $20 → 900, credits never expire
Subscription	None required. Pro ($29/mo) adds Zapier/Make webhooks, the bi-wheel, white-label, and volume
Surprise bills	None. At zero credits the widget pauses until you top up

Free widgets carry a small watermark on the chart and a "Powered by OpenEphemeris" link under it. That is how the free tier pays for itself. Pro removes both with one toggle.

I want to be clear about what you're getting, because "free calculator" usually means "someone else's branding on your page." This is the real OpenEphemeris engine, the same one developers pay to call through the API, in your house system, with your logo, on your domain. The free tier exists because I'd rather you put a genuinely accurate chart in front of your visitors than send them off to a site that gets it roughly right. Try it on a real page. The first 50 charts are on me.

— Jackson

What the calculator does

A visitor enters birth date, time, and place (place search is built in; no map keys for you to manage). About two seconds later a full natal chart wheel renders on your page: planets, houses, aspects, angles, as crisp vector graphics that follow your site's theme. Optionally interactive: hover or tap a planet and an info card explains it.

The math underneath is the same engine that serves the OpenEphemeris API: positions computed against NASA JPL's DE440 ephemeris (sub-arcsecond, 1550–2650 CE), timezone and historical DST resolved server-side from the birthplace. Not an approximation table. The chart your visitor gets matches the one you would cast in your own software.

Your house system, not the calculator's

Most free chart calculators silently render Placidus. If you work in Whole Sign or Koch, that is a problem you cannot fix.

Here you set the house system, tropical or sidereal zodiac (with your ayanamsa), and which bodies appear (classical, classical plus Chiron, or the modern set), and every chart follows your doctrine. You choose per setting whether visitors may change it, and the choice is enforced server-side, so a visitor cannot override it even from the browser's developer tools.

Theme (light, dark, mono), accent color, your logo, your own intro and footer copy: the calculator reads as part of your site, not a bolted-on box.

The part most calculators skip: the email

Turn on the email gate and the visitor is asked for their email before the full chart unlocks, with a consent checkbox that cannot be hidden or pre-ticked. Every consented lead arrives with the birth details attached, so your first reply can say something true about their chart.

Leads land in your dashboard immediately, are emailed to you within the hour, and export to CSV; on Pro they can also fire a Zapier or Make webhook straight into Mailchimp, Kit, Flodesk, or HubSpot. After 90 days we delete them from our side. More on using the chart as a lead magnet.

Installing it

Two lines, pasted once:

<script async src="https://openephemeris.com/embed.js"
        data-widget="wg_..." data-pk="pk_..." data-height="720"></script>

The dashboard generates it with your IDs filled in. It works in any HTML or code block: WordPress Custom HTML, Squarespace Code block (Business plan+), Wix Custom Code, Webflow Embed, Showit Embed Code. Platform-specific walkthroughs: Squarespace, WordPress, Wix. Every later change in the dashboard goes live without re-pasting.

Running out, and knowing before you do

If your wallet hits zero, the calculator shows a "temporarily unavailable" card until you top up, which applies instantly with no change on your site. There is no overage billing on widgets. You get an email when the balance runs low and another at zero, re-armed after every top-up, plus a banner in the dashboard.

Create a free account and the calculator is on your site in about ten minutes.