Live clock
Mars Coordinated Time and the current mission sol for the two rovers still driving on the surface: Curiosity at Gale Crater and Perseverance at Jezero Crater.
Equivalent of UTC on Mars
07:55:39
MTC ticks at the Martian-second rate at the prime meridian.
NASA MSL, landed 6 August 2012
Sol 4,929
Local Mean Solar Time
17:05:15
Mission day 4,929 since landing.
NASA Mars 2020, landed 18 February 2021
Sol 1,894
Local Mean Solar Time
13:05:27
Mission day 1,894 since landing.
Mars Coordinated Time (MTC) is the Martian analogue of UTC. It is the mean solar time at the Martian prime meridian, ticking on a Martian clock where one Martian second is about 1.027 Earth seconds. A full Martian solar day (one "sol") lasts 24 hours, 39 minutes, and 35.244 seconds in Earth time, so a Martian clock with 24 evenly spaced hours runs noticeably slower than yours. MTC is mostly a thought experiment — NASA defines it for reference and education, but no spacecraft uses MTC for operations. Rover teams schedule activities on Local Mean Solar Time (LMST) at the landing site instead, because what matters for power, thermal, and imaging is where the Sun is in the local sky.
Mars rotates more slowly than Earth. One full rotation relative to the Sun takes 88,775.244 seconds versus Earth's 86,400. The extra ~2,375 seconds add up to about 39 minutes and 35 seconds per day. Over a Martian year (687 Earth days), the difference drives every visible feature of Mars time: shorter calendars when measured in sols, longer working days when measured in Earth time, and a slowly drifting offset between any Mars clock and the equivalent Earth clock.
For a Mars surface mission, Sol 0 is landing day. Sol 1 is the first full Martian day after landing, and the count is integer sols since touchdown at the spacecraft's landing site. Mission planners use sol numbers — not Earth dates — to label commands, telemetry, downlink passes, and science targets. When a rover team says "we'll drive on Sol 4,012," they mean the 4,012th Martian day of the mission, scheduled against the rover's local sunrise and sunset, not against a calendar at JPL.
During the first months of a surface mission, the operations team often lives on Martian time so they can plan each sol while the rover is asleep and send commands when it wakes. Because a sol is ~39 minutes longer than an Earth day, their wake/sleep schedule drifts ~40 minutes later every Earth day. After about three weeks, a morning shift becomes a night shift; after six weeks, the cycle wraps around. Both Curiosity and Perseverance teams kept this schedule for roughly the first 90 sols of surface operations before returning to Earth-aligned hours.
MTC is derived from the Mars Sol Date (MSD), an analogue of the astronomical Julian Date used by NASA Goddard's Mars24 algorithm. The truncated form is MSD = (JD_UTC − 2451549.5) / 1.027491252 + 44796.0 − 0.0009626, where JD_UTC is the current Julian Date in Earth UTC. The fractional part of MSD is MTC; subtracting the longitude (in fractions of 360°) gives Local Mean Solar Time at any point on Mars. We use JD_UTC instead of JD_TT, which drifts about a minute per decade — fine for a public clock, not fine for spacecraft navigation.
For Earth-rooted versions of this question, try your age on other planets or compare planetary years and days in our orbital periods table.