Planetary Hours Calculator
Every day and night divides into 12 unequal "hours," each ruled by one of the seven classical planets. Find out which planet rules right now — and see the full 24-hour table for any date and place.
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Northern latitudes and eastern longitudes are positive. Pick the UTC offset in effect on the date below (include daylight saving if it applies).
Sunrise/sunset from standard solar position formulas (accurate to within a minute or two) · unequal "seasonal hours," not 60-minute hours · Chaldean order of planetary rulership.
What are planetary hours?
Planetary hours are one of the oldest timing systems in Western astrology, dating back to Hellenistic and Chaldean sky-watchers. Each day (sunrise to sunset) and each night (sunset to next sunrise) is split into 12 unequal "hours," and every one of those 24 hours is ruled by one of the seven classical planets — the Sun, Moon, Mars, Mercury, Jupiter, Venus and Saturn. Because daylight and darkness change length with the seasons, a planetary "hour" is rarely 60 minutes — it's simply 1/12th of that day's actual daylight, or 1/12th of that night's actual darkness.
How the ruling order works
The first daylight hour of each day is always ruled by that day's own planet — Sunday belongs to the Sun, Monday to the Moon, Tuesday to Mars, Wednesday to Mercury, Thursday to Jupiter, Friday to Venus, Saturday to Saturn. From there, every hour — day and night — cycles through the fixed Chaldean order: Saturn → Jupiter → Mars → Sun → Venus → Mercury → Moon, repeating. This is also why the weekday names themselves come from planetary rulers.
How this calculator works
Enter a location and it's geocoded (via Open-Meteo) to latitude, longitude and time zone. We calculate that day's precise sunrise and sunset using a standard solar-position formula — the same declination and hour-angle method used across astronomy software — then divide daylight and the following night into 12 equal segments each, and assign rulers using the sequence above. Times shown are local to the location you entered.
The seven planetary rulers
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☉Sun — success, vitality, leadership. Good for career moves, visibility, confidence and dealing with authority.
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☽Moon — emotion, intuition, home. Good for introspection, family matters, dreams and anything domestic.
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♂Mars — action, courage, drive. Good for exercise, competition, decisive moves and confronting challenges head-on.
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☿Mercury — communication, learning, trade. Good for writing, negotiating, studying, short trips and signing agreements.
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♃Jupiter — growth, luck, abundance. Good for money matters, education, legal affairs and big-picture planning.
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♀Venus — love, beauty, harmony. Good for romance, art, socializing, self-care and mending relationships.
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♄Saturn — structure, discipline, limits. Good for long-term planning, finishing tasks, setting boundaries and steady work.
Go deeper
See how these same seven planets shape your whole life in your Birth Chart & Natal Astrology collection, or start with the guide to reading your birth chart.
Frequently asked questions
Are planetary hours the same length as clock hours?
No. Each planetary hour is 1/12th of that specific day's actual daylight (sunrise to sunset) or that night's actual darkness (sunset to next sunrise), so the length varies by season and latitude and is only close to 60 minutes near the equinoxes.
How accurate are the sunrise and sunset times used?
We use a standard solar-position formula (solar declination and hour angle) that is accurate to within a minute or two for most locations and dates, sourced from your geocoded coordinates and time zone via Open-Meteo.
Why does hour 1 of the day match the day's name?
The weekday names themselves come from this system — the first daylight hour of Sunday is ruled by the Sun, Monday by the Moon, and so on — and every following hour, day and night, cycles through the fixed Chaldean order: Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon.
Using planetary hours in daily life
Knowing the theory is one thing — using it is another. The simplest way to work with planetary hours is to match the hour's ruler to the task at hand rather than trying to reorganize your whole day around them. A difficult email or a negotiation lands better in a Mercury hour; a first date or a design decision favors Venus; asking for a raise or stepping into a leadership moment suits the Sun. You don't need a ritual for this — just a glance at the table before you hit send or pick up the phone.
Some practices go further and treat planetary hours as timing windows for intention-setting: lighting a candle in a Jupiter hour before a big financial decision, or starting a creative project in a Sun hour for visibility. Others use them more loosely, as a check before locking in something important — a signature, a launch, a difficult conversation — the way you might check the weather before a trip. Neither approach is more "correct"; the system has been read both ways since antiquity.
A common misconception is that a "bad" planetary hour, like Saturn's or Mars's, means you should avoid acting altogether. In practice, every ruler has a constructive use: Saturn hours are excellent for finishing tasks, setting boundaries or handling paperwork, while Mars hours suit exercise, competition or any situation that calls for directness. The skill isn't picking only the "good" hours — it's choosing the ruler that actually matches what you're trying to do.