Planetary day calculator

Pick a date. The calculator uses the UTC weekday and reads the classical planet. 15 May 1990 is Tuesday and Mars. 1 January 2000 is Saturday and Saturn. 8 August 1988 is Monday and the Moon. No planetary hours and no sunrise.

A weekday-to-planet map, entertainment and tradition, not a reading. Phase: moon phase. Color: daily color. Article: Planetary day.

Input

Result

Pick a date to see the planetary day.

How it works

A planetary day in western tradition pairs the seven weekdays with the seven classical “planets”: Sun, Moon, and the five visible ones. Order: Sunday Sun, Monday Moon, Tuesday Mars, Wednesday Mercury, Thursday Jupiter, Friday Venus, Saturday Saturn.

From an ISO date we take the weekday (Sunday = 0 … Saturday = 6) and a table row. 15 May 1990 is Tuesday · Mars. 1 January 2000 is Saturday · Saturn. 8 August 1988 is Monday · Moon. 7 July 1977 is Thursday · Jupiter. 22 March 2024 is Friday · Venus. 24 March 2024 is Sunday · Sun.

The weekday mapped to the planet that rules it. We do not compute planetary hours from sunrise and we do not ask for latitude. The same planet returns every seven days.

Weekday names in many languages still carry these ties (Saturday / Saturn). Here the classical Chaldean list stays. This is not moon phase and not a Sun sign. Daily color is a separate modulo 12.

One field: date as YYYY-MM-DD. Click Calculate. For an ordinary civil date the UTC weekday matches the local calendar weekday.

Treat the result as a weekday and planet-mythology exercise. Do not read it as a prophecy or a day’s instructions.

Formula

dow = weekday(date) (0=Sunday .. 6=Saturday)

planet = Chaldean_table[dow]

Table: Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn.

No planetary hours, time zone math or geographic latitude.

How to use

  1. Pick the date in the date field, YYYY-MM-DD. The hint is 1990-05-15.
  2. Click Calculate. The result is the weekday and the planet from the Chaldean table.
  3. Check 15 May 1990: Tuesday and Mars.
  4. For Saturday, open 1 January 2000: Saturn. For Sunday, 24 March 2024: Sun.
  5. Optionally pair moon phase or daily color for the same date.

Weekday and a classical planet

15 May 1990 is Tuesday and Mars. 1 January 2000 is Saturday and Saturn. A UTC calendar, not a science forecast.

Mars
The Tuesday label. 15 May 1990 is Tuesday and Mars. No planetary hours and no sunrise.
Saturn
The Saturday label. 1 January 2000 is Saturday and Saturn. Sunday is the Sun. Weekday alone.

Suggested uses

  • Learn the classical weekday → planet map.
  • Compare seven consecutive dates in one week.
  • Workshop entertainment: mythic labels without fortune-telling.
  • Quickly check a “day planet” before reading historical texts.
  • Calendar practice beside moon phase and Sun sign.
  • Start a talk about planetary day vs planetary hour.

Examples

Example 1

  • Date: 1990-05-15

Tuesday · Mars

Tuesday maps to Mars in the Chaldean table.

Example 2

  • Date: 2000-01-01

Saturday · Saturn

Saturday → Saturn.

Example 3

  • Date: 1988-08-08

Monday · Moon

Monday → Moon.

Example 4

  • Date: 1977-07-07

Thursday · Jupiter

Thursday → Jupiter.

Example 5

  • Date: 2024-03-22

Friday · Venus

Friday → Venus.

Example 6

  • Date: 2024-03-24

Sunday · Sun

Sunday → Sun.

Related calculators

Moon phase

Pick a date.

Use calculator →

Daily color

Pick a date (daily color).

Use calculator →

Zodiac sign

Pick a birth date.

Use calculator →

Moon sign

Pick a date (moon sign).

Use calculator →

All esoteric calculators

Frequently asked questions

What planet is 15 May 1990?

Mars. That Tuesday in the table: Sunday Sun, Monday Moon, Tuesday Mars.

What about 1 January 2000 and 8 August 1988?

2000-01-01 is Saturday and Saturn. 1988-08-08 is Monday and the Moon.

Is this a scientific forecast?

No. It is a weekday label. Not an ephemeris and not a reading.

Do you compute planetary hours?

No. Hours need sunrise and a place. Here only the weekday.

What is the full order?

Sunday Sun, Monday Moon, Tuesday Mars, Wednesday Mercury, Thursday Jupiter, Friday Venus, Saturday Saturn.

What about 7 July 1977 and 22 March 2024?

1977-07-07 is Thursday and Jupiter. 2024-03-22 is Friday and Venus.

Does time zone change the planet?

We take the weekday from the ISO date (UTC). For an ordinary civil date it matches the local weekday.

How is this different from moon phase?

Phase is disc lighting. Here a weekday label, even at new moon.

Is 24 March 2024 the Sun?

Yes. That Sunday. The same planet returns a week later.

Is a blank date Sunday and the Sun?

No. Without a date there is no weekday. Pick a day on the calendar.

Knowledge sources

The calculator reads a date or a tradition table. This is not fortune-telling, not an astrologer’s chart and not a diagnosis.

Page updated in 2026.