How to Calculate Your Planetary Hours

So you know what planetary hours are, and now you want to find yours. Good news: you don’t need a math degree or a telescope. You just need a few numbers and a little patience. Here’s exactly how to calculate planetary hours for any day, anywhere.

What You Need First

Before you calculate planetary hours, grab two numbers for your exact location: today’s sunrise time and today’s sunset time. You can find both in seconds with a quick weather app search or a sunrise-sunset website. Write them down. You’ll use them for every step below.

Step 1: Find Your Daylight Hour Length

Here’s the easiest way to do this without getting confused. First, convert both your sunrise and sunset time to 24-hour format. Your sunrise time stays exactly the same. For your sunset time, just add 12 to the hour. So 8:00 PM becomes 20:00.

Now subtract your sunrise from that 24-hour sunset number. Using our example: 20:00 minus 6:00 equals 14 hours of daylight.

Turn that into minutes by multiplying by 60. 14 hours equals 840 minutes.

Finally, divide by 12. 840 divided by 12 equals 70 minutes. That’s the length of one “daytime planetary hour” for today.

Step 2: Find Your Nighttime Hour Length

Now do the exact same steps for the night. Convert tomorrow’s sunrise to 24-hour format, then add 24 to it since it falls on the next day. In our example, tomorrow’s 6:00 AM sunrise becomes 30:00.

Subtract today’s sunset (20:00) from that number: 30:00 minus 20:00 equals 10 hours of darkness.

Turn that into minutes: 10 hours equals 600 minutes.

Divide by 12: 600 divided by 12 equals 50 minutes. That’s the length of one nighttime planetary hour.

Step 3: Find Which Planet Rules Today

Every day of the week has a ruling planet, and that planet always rules the very first hour after sunrise:

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

Step 4: Follow the Planet Order

Starting with your day’s ruling planet, the hours cycle through this order, over and over, all day and all night:

Saturn → Jupiter → Mars → Sun → Venus → Mercury → Moon

So if it’s Wednesday, your first daytime hour belongs to Mercury. Your second hour moves to the next planet in the list after Mercury, which is the Moon. Keep counting forward through the list for each hour that passes, looping back to Saturn after Moon, all the way through your 12 daytime hours and into the 12 nighttime hours.

The Quickest Way to Get Your Answer

Now that you know how the math works, here’s the good news: you don’t actually have to do it every single time. Even if you’re comfortable running the numbers yourself, our free planetary hours calculator is the fastest and easiest way to get your answer without any risk of a math mistake along the way. Just plug in your city, and it instantly runs every step above for you, sunrise and sunset included.

What’s Next

Now that you can calculate planetary hours for yourself, you’re ready to start using them on purpose. Our next guide, Best Planetary Hours for Love, Money & Communication, breaks down exactly which hour to use for which goal.