Cosmic Almanac · Observatory

Your Birth Chart, Alive

A real chart, rendered from the sky. Tap any planet or sign to learn what it means — on this chart.

Sample chart · a place to start
Hover a planet to explore · tap to pin it
This is a sample chart. Yours is drawn from your birth details.

Reveal your sky

The exact moment and place you were born.

About this calculator

What this birth chart calculator gives you

A birth chart is a map of the sky at the exact moment and place you were born. This one draws that map live, from your date, time and birthplace — free, and without an account.

What appears on the wheel:

On the chartWhat it is
10 bodiesSun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto, each placed at its true position
Your rising signThe sign coming over the horizon at your birth — the chart is built outward from it
12 housesWhole sign houses: one sign to a house, counted from your rising sign
RetrogradesOpen any planet and it tells you if it was retrograde — appearing to move backwards — on your birth date
5 aspectsConjunction, sextile, square, trine and opposition — drawn as lines across the wheel

Hover or tap any planet to see where it sits and what that placement means. The lines between planets are the aspects — the conversations the planets are having with each other.

Why it asks for your birth time

Most free chart tools treat birth time as optional. It isn't, and this is the single biggest reason two charts for the same person can disagree.

The rising sign moves about one degree every four minutes. The sky rotates a full circle in roughly twenty-four hours, so the horizon advances fifteen degrees an hour. A birth time that is two hours out will usually put your rising sign in a different sign altogether — and because the houses are counted from the rising sign, every house in the chart shifts with it.

The planets barely move in that time. The Moon is the exception: it travels about half a degree an hour, so it can change sign within a day.

If you don't know your birth time exactly. Use the closest time you have and treat the house positions as provisional — the planets and their signs will still be right. A birth certificate, hospital record or family memory is worth chasing down before you take any house-based reading seriously.

The birthplace matters for the same reason. The horizon depends on where on Earth you were standing, so the same moment produces a different rising sign in Mumbai and in London.

Why your chart may not match another site

If you have used another calculator, some placements here may look different. That is usually not an error — it is a different zodiac.

There are two conventions. The tropical zodiac fixes the signs to the seasons. The sidereal zodiac fixes them to the constellations as they actually sit today. The two have drifted roughly twenty-four degrees apart over the centuries, which is close to a full sign — so a late-degree tropical Leo is often a sidereal Cancer.

This calculator uses sidereal positions, measured with the Lahiri method, for the planets and the rising sign alike. Most Western sites use tropical. Neither is a mistake; they are answering the question in different traditions, and Cosmiclogy uses one consistently rather than mixing them.

Reading the wheel

That is enough to orient yourself. For how to actually interpret what you are looking at — which placements to read first, and how to weigh them — the full guide goes further.

Full guide
How to Read a Birth Chart
Astrology
Your Rising Sign
Astrology
The Twelve Houses
Astrology
Aspects Explained
Astrology
The Planets
Astrology
Your Moon Sign

Questions people ask

Is this birth chart calculator free?

Yes. There is no sign-up and no payment. Your details are used to calculate the chart and are not saved to any account.

Do I need my exact birth time?

For the planets and their signs, no — those barely move over a few hours. For the rising sign and the houses, yes. The horizon advances about one degree every four minutes, so an hour or two of error usually moves the entire house structure.

Why is my rising sign different here?

Either the birth time is different from the one you used elsewhere, or the other site uses the tropical zodiac while this one uses sidereal. The two run roughly a sign apart.

Which house system does it use?

Whole sign houses — the oldest system, and the one used throughout Cosmiclogy. Each sign is one complete house, starting from the sign on your horizon.

Can I calculate a chart for a child?

No. Charts are calculated for adults only, and a birth date under eighteen years old will be declined.

What are the coloured lines?

Aspects — the angles between two planets. Conjunction (same place), sextile (60°), square (90°), trine (120°) and opposition (180°). Each is drawn in its own colour so you can pick out the pattern at a glance.