Planetary Hours Calculator

Understanding Planetary Hours

Planetary hours are an ancient astrological system that assigns rulership of each hour of the day to one of the seven classical planets (Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn). This system has roots in Chaldean astrology and was widely used in Hellenistic, medieval, and Renaissance magical traditions.

How Planetary Hours Work

Unlike standard clock hours, planetary hours divide daylight and nighttime into 12 equal parts each, regardless of the season. This means that daytime planetary hours are longer in summer and shorter in winter, while nighttime hours follow the opposite pattern.

The sequence of planetary rulers follows what's known as the "Chaldean order," based on the apparent speed of the planets as observed from Earth:

1. Saturn (slowest)
2. Jupiter
3. Mars
4. Sun
5. Venus
6. Mercury
7. Moon (fastest)

The first hour of each day begins at sunrise and is ruled by the planet that rules the day itself:

• Sunday: begins with the Sun hour
• Monday: begins with the Moon hour
• Tuesday: begins with the Mars hour
• Wednesday: begins with the Mercury hour
• Thursday: begins with the Jupiter hour
• Friday: begins with the Venus hour
• Saturday: begins with the Saturn hour

After the first hour, the sequence continues in Chaldean order, repeating throughout the 24 hours of the day. This is why each day of the week is ruled by a specific planet—the planet ruling the first hour of that day.

Applications of Planetary Hours

Throughout history, planetary hours have been used for various purposes:

• Magical Timing: In traditional magic and alchemy, operations were timed to correspond with appropriate planetary hours to enhance their effectiveness.
• Medical Treatments: In medieval and Renaissance medicine, certain treatments were administered during specific planetary hours believed to strengthen their efficacy.
• Business and Legal Matters: Important transactions or legal proceedings were sometimes scheduled during favorable planetary hours.
• Prayer and Meditation: Religious and spiritual practices were often aligned with specific planetary hours for maximum spiritual benefit.
• Daily Planning: Some practitioners still use planetary hours to plan their days, scheduling activities that align with the energy of each hour.

Practical Usage Today

While the scientific basis for planetary hours is not recognized by modern science, many people still find value in this ancient system as:

• A way to attune to natural cycles and cosmic rhythms
• A framework for organizing daily activities in harmony with subtle energetic influences
• A tool for timing important actions or decisions for optimal outcomes
• A practice that connects us to ancient wisdom traditions
• A means of working consciously with different qualities of time

Whether approached as a literal system of cosmic influence or as a symbolic framework for organizing time, planetary hours offer a fascinating window into how our ancestors understood the relationship between celestial movements and earthly affairs.