Free birth chart calculator
Your birth sky with what almost no calculator shows: sect, essential dignities and receptions. The calculation is free; the AI of Efémeris can then turn it into a personalised classical reading.
What a birth chart is
A birth chart is a photograph of the sky at the exact moment and place of your birth: where each of the seven traditional planets stood, which sign was rising over the horizon —your ascendant— and how the twelve houses were divided. Three pieces of data are needed to calculate it: the date, the local time and the place. With the exact time, the chart is exact; without it, the ascendant stays approximate and we say so.
What this calculator shows that others don't
Efémeris works in the Hellenistic line: seven planets for the judgement, and the outer planets as sensitive points. That is why the result includes the sect of your chart —whether it is diurnal or nocturnal, which changes what planets play in your favour—, the essential dignities of each planet with their five levels, the receptions —the rescue mechanism of classical astrology— and the seven Hermetic lots, starting with the lot of Fortune, with the formula reversed in a nocturnal chart as tradition requires: a detail many calculators overlook.
The time zone is resolved by coordinates and with history. The zone of a place changed over the years, and using the current one for an old date can shift the ascendant by a whole sign — it is one of the most common errors in charts calculated online.
How to read the result
Start with the four coordinates: the Sun (who you are), the Moon (what you need), the ascendant (how you enter the world) and the midheaven (where you are heading). Then look at the condition: a planet in its own domicile does not work like one in fall. Every item in the result links to its own page, so you can go deeper at your own pace: the signs, houses and planets are explained one by one, and the techniques of the tradition have their own chapter.
If you want to move from the data to a synthesis, see how AI astrological interpretation in Efémeris works: the engine supplies the whole chart and the AI works on that context alone.
Frequently asked questions
Do I need to know my birth time?
It isn't required, but it matters: without the time, the ascendant and the houses are approximate. If you don't know it, we calculate the chart at noon and flag it — the Sun, and the planets in general, move little in a day; the ascendant changes sign every two hours.
What house system does the calculator use?
Placidus by default, and you can switch to whole sign houses (the system of Hellenistic astrology) before calculating. The two divisions differ in many placements, so the selector is right there in view.
Why does this calculator show sect and dignities?
Because they are the basis of judgement in classical astrology. Sect says whether your chart is diurnal or nocturnal — and that changes which planets play in your favour. Essential dignities measure the strength of each planet according to where it stands. Most calculators don't show them.
How does it resolve the time zone?
By coordinates and with history: the time zone of a place changed over the years, and using today's for an old date can shift the ascendant by a whole sign. Uruguay, for instance, was on GMT−2 in 1979. The calculator uses the zone that was in force on your date of birth.
Do you store my birth data?
No. The chart is calculated in your browser and nothing is stored on any server. If you share the link to your chart, the data travels in that URL — share it only with whoever you want.
What's the difference between this chart and the Efémeris reading?
The calculator gives you the complete data: what is in your chart and in what condition. With an account, the AI of Efémeris interprets those calculations from classical astrology, connects the chart with techniques of the year such as profection or the solar return, and lets you ask questions about your own sky.
How does Efémeris use artificial intelligence?
The AI doesn't invent positions and doesn't replace the astrological engine. It receives the calculations of your chart as context —planets, houses, aspects, sect, dignities and cycles— and organises them into a personalised reading grounded in the classical tradition.