Mars Time

Airy Crater (MTC)

Utopian Martiana Calendar

Year  ,  Month  ,  Day

Name of Day




Earth Time

Greenwich (UTC)

Gregorian Calendar




Clocks Developed by Shaun Moss and Thomas Gangale

An Explanation of Martian Timekeeping

image    The Martian Federation and Mars Registry use a modified version of the Martiana calendar, invented by aerospace engineer and political scientist Thomas Gangale in 2002 from an earlier version he created in 1985. Our calendar combines Gangale's Martiana calendar with the nomenclature of the Utopian/Kepler version of the Darian calendar. Our clocks were developed by Shaun Moss and Thomas Gangale.

The Martian Day
The average length of a Martian solar day (called a sol) is 88,775.24409 seconds or 24h 39m 35.24409s. The corresponding value for Earth is 24h 00m 00.002s. The Martian Federation and Mars Registry use a system in which the longer Martian day is stretched evenly to retain a 24-hour day with each hour divided into 60 minutes, then each minute divided into 60 seconds. Martian hours are called spells, minutes are called moments, and seconds called jiffies.

The Martian Week
The Martian week is divided into seven days, like Earth's, but the names are different to avoid confusion with the home planet. Sticking with the Utopian/Kepler convention, Day 1 is called Sunsol, Day 2 is called Phobosol, then Deimosol, Terrasol, Venusol, Mercurisol, and Jovisol. The days of the week cycle continually (unlike the original Darian calendar). Because a Martian day lasts 39 minutes longer than Earth's, the days of the Martian week are frequently out of sync with the days on Earth.

The Martian Year
A Martian year is 668 or 669 Martian days (sols) long, or 687 Earth days long. It is divided into 24 months that last for 27 or 28 days each. The names of the months alternate between the zodiacal signs of Mars in relation to the Sun, and other various constellations. Every other year is a leap year, with an extra day added on odd years to Draco, the last month. Another leap day is added to an even year every ten years. The first day of the Martian year begins at roughly the vernal equinox (this can vary slightly by a few days depending on the year).

The Martian year is numbered from the Martian vernal equinox of the Earth year 1610 AD. Thomas Gangale and several others chose this time because it is the year that Kepler published his first two laws of planetary motion, and it is the year that Galileo noted the phases of Mars with his telescope. It is now the 214th Martian year since March 11, 1610.

Use of the Calendar
While Martian settlers would use this calendar for their day-to-day business, most would still utilize the Earth calendar on a frequent basis to conduct business with the home planet and/or to observe religious holidays and holy days of the week. Most wall calendars on Mars would likely show the Martian dates along with the Earth days offset beneath, as the transitions only line up on rare occasions.

Free Martian Calendar: See What Day it Really is on Mars and Earth!

Mars Calendar Year 215

Mars and Earth Date Calculator

  The Mars and Earth Time and Date Calculator shows a map of Earth's and Mars' orbits around our sun on a given date. By default the map shows the planetary configuration for today's date. To see other dates and times, use the calculator below to convert Earth times to Martian times and vice versa. The displayed seasons are from each planet's northern hemisphere. The calculator was developed some years ago by by Alan Hensel and Thomas Gangale.



Mars and Earth Time and Date Calculator
Earth Date (Gregorian)
Year Month Day
Time : :
   Day of the Year
Julian Day

Mars Date (Utopian Martiana)
mYear mMonth Sol
Time : :
   Sol of the mYear
Julian Sol
Calculator Developed by Alan Hensel and Thomas Gangale