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). Unequal Houses: Many of these systems use the time it takes planets to move through the sky to divvy up the houses. 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.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). 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. Each house will be offset from a zodiac sign by the same amount. Equal House: Houses in this system may not align exactly with the zodiac signs, but they are still all the same size.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). Whole Sign: In this system, each house lines up with an entire zodiac sign.X Research source Popular Equal House systems include: 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. All 12 houses are evenly divided into 30 degree sections of the wheel, and calculations are easy to do by hand. Equal Houses: These systems tend to be simple, elegant, and easy to read on a birth chart.

5th house astrology calculator