What Is House Calculation in Astrology? Houses Explained

Co-authored by Angel Eyedealism and Dan Hickey

Last Updated: June 20, 2022

The houses of your birth chart provide lots of information about your life and personality, but did you know they might be in different places depending on who you ask? Many house calculation methods have been created over the centuries to determine exactly where the boundaries between each house are. If you’ve ever wondered how astrologers calculate these angles and what the implications are for your birth chart, this is the article for you! Read on to learn more about the houses, popular calculation methods, and how they influence your chart.

Section 1 of 6:

What are houses?

Houses are sections of the sky determined by your birth time and location. There are 12 houses in most calculations, each corresponding to a different aspect of your life. The sun, moon, and planets are located within the houses (their exact placement is determined by where they were at your moment of birth). Their interactions with the houses has a great impact on the events of your life.^{[1]
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- On a birth chart (also called a natal chart), the 12 houses are arranged in a counterclockwise ring according to your perspective view of the sky at the precise time and location you were born.
- The circular house chart is not the same as a zodiac wheel, which is based on the sun’s observable path around the earth. Houses are determined by the Earth’s own 24-hour rotation.

Section 2 of 6:

The 12 Houses in Astrology

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The 1st House: This house is always found on the eastern horizon and contains your Ascendant (the sign that was on the Eastern horizon when you were born). This house governs your identity—what it feels like to be you, how you express yourself, even your appearance and wellness.
- This house is embodied by the energy of Aries and its ruling planet, Mars.
- Your Ascendant sign is very important. It’s your personality and persona, your social standing, and the way you look at things. It also determines your Descendant (the sign on the Western horizon when you were born, 180 degrees away from the Ascendant), which determines who you’re attracted to and get along with.
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The 2nd House: The next house governs your relationship with income. That can refer to actual money and possessions, or in a more philosophical sense, the things that feed you (like fulfilling relationships or a cause you care about). It also affects your sense of security and is representative of your self-worth.
- This house is embodied by the energy of Taurus and its ruling planet, Venus.
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The 3rd House: This house is all about your communication style. It determines how you talk, use social media, and communicate with friends and family. Everything to do with your 3rd house feels familiar and energetic.
- This house is embodied by the energy of Gemini and its ruling planet, Mercury.
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The 4th House: Located at the bottom of the sky (the place where the sun goes at midnight), this house is all about home and family. It determines how you create your safe space and your feelings toward relatives, ancestry, and lineage. Your roots are located in this house.
- This house is embodied by the energy of Cancer and its ruling planet, the Moon.
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The 5th house: This house governs pleasure in the romantic, sexual, and creative sense. This is where you feel good, and good things come to pass for you. People with strong 5th house placements often live lives full of fun and joy.
- This house is embodied by the energy of Leo and its ruling planet, the Sun.
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The 6th House: Your sense of maintenance and routine are rooted in this house. Your daily chores and work habits stem from here, as well as your relationships with coworkers and employees. This is also where you manage illness, injury, and fitness.
- This house is embodied by the energy of Virgo and its ruling planet, Mercury.
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The 7th House: This house is your Descendant, located opposite your Ascendant. It has the most sway over your relationships—friends, families, partners, and enemies—and is where you find love. It is also associated with death, since this is where the sun sets in the western sky.
- This house is embodied by the energy of Libra and its ruling planet, Venus.
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The 8th House: Known as the house of debt, this is the place where you deal with generosity and loss. You face unavoidable events in this house, like death or taxes, and are often dealt the question “Is this worth it?” when weighing a decision that might put you in debt.
- This house is embodied by the energy of Scorpio and its ruling planet, Pluto.
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The 9th House: This house governs how you travel and pursue knowledge and higher education. It’s a house full of joy, and people with strong placements here tend to be leaders in academia, philosophy, or religion. This is where your beliefs shape the world around you.
- This house is embodied by the energy of Sagittarius and its ruling planet, Jupiter.
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The 10th House: The cusp of this house is located at Midheaven (the point in the sky where the sun is the highest at noon). This house is all about your career, public image, and reputation. This is where you shine, show off, and get recognition.
- This house is embodied by the energy of Capricorn and its ruling planet, Saturn.
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The 11th House: This is where you find the people who support you in life—your friends, family, colleagues, and audience. This house facilitates collaboration and connection with like-minded people and is where your dreams and visions can be achieved.
- This house is embodied by the energy of Aquarius and its ruling planet, Uranus.
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The 12th House: This is the house of your unconscious. Just as the 1st house is all about who you are, this house governs things out of your control. It values structure and is a place where you sacrifice your own needs for the good of the group. Here, you learn to let go.
- This house is embodied by the energy of Pisces and its ruling planet, Neptune.^{[2]
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Section 3 of 6:

Why are house calculation methods different?

The various methods differ based on the philosophy and preferences of the astrologers who invented them. Many yield similar results to each other, but some can create noticeably different charts. Almost all methods begin by identifying the degree where the 1st house begins on the eastern horizon and then calculating the remaining houses moving counterclockwise. The math involved can range from simple to very complex.
- Calculation methods can be broadly split into 2 groups: Equal House systems where all houses are uniform in size, and Unequal House systems where house sizes can vary.

Section 4 of 6:

Calculating the Houses

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Equal Houses: These systems tend to be simple, elegant, and easy to read on a birth chart. All 12 houses are evenly divided into 30 degree sections of the wheel, and calculations are easy to do by hand. These methods work well for people born near the poles (above or below 66 degrees from the equator) since some signs never touch the horizon in these regions.^{[3]
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Research source} Popular Equal House systems include:
- Whole Sign: In this system, each house lines up with an entire zodiac sign. The 1st house spans your entire Ascendant sign, your 2nd house spans the entire following sign, and so on (mathematically, the cusp of each house is at 0 degrees of its corresponding zodiac sign).
- Equal House: Houses in this system may not align exactly with the zodiac signs, but they are still all the same size. Each house will be offset from a zodiac sign by the same amount. This amount is determined by the degree of the Ascendant at birth (for example, say your Ascendant sign is Gemini and it had risen 5 degrees when you were born. The cusp of your 1st house would be 5 degrees Gemini, the cusp of your 2nd house would be 5 degrees Cancer, and so on).
- One downside of Equal House methods is that the Midheaven degree (usually the cusp of the 10th house, where the sun is highest in the sky) can move around to other houses.
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Unequal Houses: Many of these systems use the time it takes planets to move through the sky to divvy up the houses. They use the Ascendant/Descendant line and the Midheaven/IC (bottom of the sky) line as cusps for the 1st, 4th, 7th, and 10th houses (think the X and Y axes on a graph). The other cusps can occur at irregular angles since their locations are based on the amount of time each sign spends on the horizon from the perspective of Earth. Popular Unequal House systems include:
- Placidus: The cusp of the 1st house is the degree of the zodiac sign rising at birth. Over the course of 12 hours from birth, the degree of the horizon is measured every 2 hours to mark the cusp of the next 6 houses. Those lines are then extended across the birth chart to complete the remaining 6 houses.
- Koch: This method works like Placidus, except it uses Midheaven as the starting point instead of the Ascendant. Its results are very close to what you’d get with Placidus, but planets can change houses if they are close to the cusps.
- Porphyry: The cusps of the intermediate houses are based on the number of degrees between the Ascendant and Midheaven. That number is divided by 3, and lines are drawn across the chart to mark your 12th, 11th, 5th, and 6th houses. So if there are 84 degrees between Midheaven and the Ascendant, each house is 28 degrees wide.

Section 5 of 6:

Which calculation method should I use?

It’s completely up to you! Use whichever method you’re most comfortable or familiar with, or whichever method gives you an interpretation of your chart that resonates with you. Think of the different calculation methods as filters on an Instagram photo—they all reveal the same truth, just from a different perspective.^{[4]
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- Compare multiple readings to see which you identify with. Online birth chart calculators make it fast and easy to compare charts created with different house calculations.
- The location of your birth might influence which method works best. A Placidus or Koch chart creates wildly unequal house sizes for people born near the poles, so a Whole Sign or Equal House chart might work better.
- If you’re calculating houses by hand, systems with simpler math (Whole Sign, Porphyry) might be easier to determine than those with complicated math (Koch, Placidus). However, online house calculators make using any system a breeze.

Section 6 of 6:

Interpreting Your Chart with Houses

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The sun, moon, and planets are located in different houses at birth. Each planet embodies different aspects of your being (like a warrior, a lover, or a scholar) and the way they interact with the houses can have a big impact on your life. Some houses may have multiple planets in them while some have none. Here are some example interpretations of planets in houses:
- Say you have Mars in your 1st house (the house of self). Mars is a soldier that represents action, fitness, and aggression. This could be interpreted as you having the willpower and assertiveness to accomplish your personal goals.
- Imagine Saturn in your 3rd house (the house of communication). Saturn is responsible and cares about rules and obligations. This might mean you have a tendency to communicate very logically with the goal of accomplishing important tasks.
- Your birth chart shows where your interests lie and where you're drawn. By examining certain houses and certain signs and certain planets in the chart, you can map out a course for your life, even including a list of possible careers!
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Each house is also ruled by a zodiac sign. The sign depends on which zodiac constellation was rising at the time of your birth (your Ascendant sign). The ruling sign influences how the planet behaves and speaks more to your personal traits. For example:
- Imagine Mars in your 1st house ruled by Gemini. You have the willpower to accomplish your goals, and your method of getting what you want will probably involve Gemini’s witty, chatty, dualistic nature.
- Picture Saturn in your 3rd house ruled by Taurus. You communicate logically to accomplish a goal, but may be slow, static, or stubborn like Taurus in your negotiations.