Planetary Hour Calculator

What are planetary hours?

Planetary hours are an ancient system dating to Hellenistic astrology that divides each day into 24 hours, each ruled by one of the seven classical planets (Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn). The system uses the Chaldean order — the sequence of planets by perceived speed — to assign rulers. The hour at sunrise on each day is ruled by that day's planet (e.g., Sunday's first hour is ruled by the Sun, which is where the name "Sunday" comes from).

What is the Chaldean order?

The Chaldean order arranges the seven classical planets from slowest to fastest as observed from Earth: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon. This order was used in ancient Mesopotamia and forms the basis of the planetary hours system. Every 7 hours the cycle repeats, meaning the same planet rules the same hour 24 hours later.

How do I use planetary hours practically?

Practitioners schedule activities to match planetary energies: financial meetings during Jupiter hours, creative work during Venus hours, important communications during Mercury hours, physical exercise during Mars hours. This is a traditional timing system used in electional astrology and ceremonial magic, and is not scientifically validated — treat it as a mindful framework for intention-setting.