How to read a natal chart, step by step

Check the birth details first

A natal chart represents celestial positions for the time and place of birth. The calculation needs a date, local time and birthplace. The time zone and historical daylight saving rules are also part of the calculation.

Record where the time came from: a document, a relative’s memory or an approximate interval. “Around six in the morning” has a different precision from a recorded 06:03. Keep an honest interval instead of inventing minutes.

Open the natal chart calculator and check the input before reading the interpretation. This lesson explains the chart itself; the product page describes the available personal analysis.

Compare charts with the same settings

Two websites may show different houses for the same birth details if they use different systems. Check the zodiac, house system and calculation settings before treating a difference as a contradiction.

The tropical zodiac begins at the March equinox; sidereal systems use a different reference. Equal houses, whole signs and Placidus are also different systems. Save the settings beside every chart you compare.

Find your way around the wheel

The outer ring contains the signs. A separate division shows the houses. The position table gives a more precise location for each body. Lines between positions may show aspects when that display is enabled.

The diagram below was constructed for teaching. It uses an ascendant at 15° Gemini and equal houses. Each house begins 30° after the previous one, so the house boundaries are offset from the sign boundaries.

Build one reading in order

In this example, Mercury is at 16° Aries. The eleventh house begins at 15° Aries, so Mercury is in that house. At 14° Aries, with the same settings, it would be in the tenth.

That is the geometric step. A symbolic reading might then consider initiative in conversations with friends or groups. Add the aspects and other placements before drawing a conclusion. Ask which situations fit the description and which do not.

Continue with houses for areas of life and aspects for relationships between positions. An isolated placement leaves out the rest of the chart.

What remains uncertain without a birth time

The ascendant and houses depend on time and place. Without a birth time, do not present them as established personal positions. The Moon may also have changed signs during that day; near a boundary, check the full possible interval.

Compare charts for the beginning and end of the known interval. Record what stays the same and what changes. This shows the uncertainty; it does not recover a missing birth time.

The birth chart and today’s positions

The birth positions remain the reference. Positions calculated for another date can be compared with them. This is the basis of a transit reading.

A natal chart is not a diagnosis, an ability assessment or proof of a predetermined life. Compare any proposed decision with the facts, your needs and the options actually available to you.