The Astrolium chart generator is the free entry point to the workspace. Drop in a birth date, time, and place; the wheel renders in under 300 ms with the Swiss Ephemeris under the hood. 23 house systems are switchable from 1 dropdown, the 20,000 named asteroid layer toggles on with 1 click, and the chart works in any modern browser on Mac, Windows, iPad, Linux, or Android.
No signup. No email. No upload. The math runs in the same engine the $29 per month Pro plan uses, so the positions you see here are the positions a working practitioner would see on the desktop equivalent (Solar Fire or Astro Gold) to the arc second.
For the full feature set around the chart, see the natal chart feature. For the reading method, read the how-to-read-a-natal-chart guide. For the timing layer (profections, Zodiacal Releasing, transits), see predictive timing. For the partnership view, see the synastry calculator or the synastry feature.
What the generator returns
The wheel defaults are tuned for a working chart, not a souvenir. The 10 bodies (Sun through Pluto), Chiron, Lilith, the angles, Mean Node, and the classical 4 asteroids (Ceres, Pallas, Juno, Vesta) are on the wheel by default. Whole Sign houses are the default house system; the dropdown covers Placidus, Koch, Equal, Porphyry, Regiomontanus, Campanus, Alcabitius, Morinus, and 14 more.
One click away: the 20,000 named asteroids (queryable by name or number), the Robson and Brady fixed-star catalogs, the 7 Hermetic Lots, the Bonatti 97 Arabic parts, midpoint trees, declinations, antiscia, and the harmonic charts (1 to 12). Solar Fire treats the asteroid catalog as a paid add-on; here it ships free.
How the math works
The chart generator runs on Swiss Ephemeris, a re-implementation of NASA JPL's DE431 ephemeris that astrologers, astronomers, and spacecraft missions all use. Accuracy is better than 1 arc second across the period 13201 BC to AD 17191. Solar Fire (since v8) and Astro Gold use the same library, which is why a chart cast in Astrolium and the same chart cast in Solar Fire match planetary longitudes to a precision tighter than any wheel can render visually.
House cusps depend on the system you pick. The Astrolium implementation tracks the canonical formulas in the Hand-Schmidt house systems reference and matches Solar Fire and Astro Gold for every standard system. The cusps for the less common systems (APC, Krusinski, Carter Poli-Equatorial) have been cross-validated against the Hand reference within 0.01 degrees.
The time zone is the one place a free chart generator can quietly go wrong, and most do. Astrolium geocodes the birth location against a 2.7 million row gazetteer, then applies historical time zone rules for the birth year. A birth in 1971 New York uses 1971 EST/EDT, not the post-2007 rules. Wartime offsets, daylight saving exceptions, and local solar time corrections for pre-1900 births are all handled. If the geocoded lookup disagrees with what the birth certificate says, you can override the time zone in 1 click.
Where the free chart ends and Pro begins
The free tier:
- Cast unlimited charts.
- Render the wheel with the 10 bodies, the angles, the nodes, and the classical 4 asteroids.
- Add the full 20,000 asteroid layer, fixed stars, and Arabic parts on demand.
- Switch among the 23 house systems.
- Export a PNG of the wheel and a 2 page PDF interpretation.
Nothing is stored. Each chart is generated for that browser session and discarded when you close the tab. No email, no card, no account.
The Pro tier ($29 per month, or $14.50 founding) adds the workspace around the chart:
- Save to a client profile. Every chart you cast attaches to a client in the CRM, alongside session notes, intake, and consent.
- AI interpretation. A 1,800 to 2,500 word draft from the AI assistant, in 9 languages, with citations to the chart positions it is reading from.
- Predictive ribbon. Profections, Zodiacal Releasing, and transits stacked on a scrubbable timeline from 1900 to 2100.
- Synastry and composite. Cast a synastry against any other client in 2 clicks. See the synastry feature for the workflow.
- Shareable client links. A live URL the client opens in any browser. Pro can password-protect and set an expiry between 1 hour and 1 year.
The free chart is the same math the practitioner uses. The Pro plan is everything around the chart that turns a calculator into a practice.
Versus the free web charters
Astro-Seek, Astrodienst, and Cafe Astrology all use Swiss Ephemeris, so the positions match Astrolium to the arc second. Astro-Seek is fast but the UI is a 2008 ad-heavy table. Astrodienst is the reference and paywalls the extended modules. Cafe Astrology is friendly for beginners and thin for professionals. None of the three has a save target or a Pro upgrade path. The Astrolium free chart is the entry to a working-practitioner workspace, not a souvenir wheel.
Continue exploring
- Natal chart feature — what the chart looks like inside a Pro workspace
- How to read a natal chart — the reading method
- Synastry calculator — the partnership equivalent
- Saturn return calculator — the predictive equivalent
- Best astrology software 2026 — the full market roundup