Baktuns to Days (baktun to d)

1 baktun equals 144,000 days exactly.

1 baktun = 144,000 days

How to convert baktuns to days

To convert baktuns to days, multiply the number of baktuns by 144,000. This factor is exact. To go the other way, multiply days by 0.000006944444444 (rounded).

days = baktuns × 144,000

Example: 10 baktuns = 1,440,000 days.

Months and years are not constant. This site uses the average Gregorian year of 365.2425 days, so one 'year' converts to 365.2425 days, not 365; use 'common year' for exactly 365 days.

About these units

Baktun (baktun)

MayaHistorical unit (no longer in standard use)

20 katuns or 144,000 days (about 394 years). The Long Count completed 13 baktuns on 21 December 2012, a date misread as a doomsday prediction.

The largest unit in everyday Long Count use, the baktun spans 20 katuns, or 144,000 days, about 394.26 tropical years. Dates are written with the baktun count first, so a monument reading 9.15.10.0.0 sits in the ninth baktun, and the Classic period of Maya civilization fell mainly in the eighth and ninth.

Public attention came when the count reached 13.0.0.0.0 on 21 December 2012, under the widely used GMT correlation. Popular writers called it the end of the world, but scholars note there is no evidence the Maya expected that, and the count simply moved on to 14.0.0.0.0. The next such milestone falls in March 2407.

A naming quirk follows from the numbering. The Long Count starts counting from zero, so the baktun that began in 2012 is strictly the fourteenth, though it is usually called the thirteenth. J. Eric S. Thompson judged that usage inaccurate but too entrenched to change. Larger cycles such as the piktun, at 20 baktuns, are rarely attested, and their names are modern coinages.

1 baktun = 12,441,600,000 seconds (exactly).

Sources: Wikipedia: Baktun; Wikipedia: Mesoamerican Long Count calendar; Wikipedia: Maya calendar

Day (d)

Metric (SI)Current unit

24 hours or 86,400 seconds. The mean solar day; the actual rotation of the Earth is about 4 minutes shorter (see sidereal day).

Old English dæg is the root of our day, with close cousins in German Tag, Dutch dag and Icelandic dagur, all descending from Proto-Germanic dagaz. It is the oldest unit here, because the cycle of light and dark needs no instrument. Yet the day we count is a constructed average: the actual interval from one noon to the next varies through the year by up to about 7.9 seconds, because Earth's orbit is elliptical and its axis is tilted.

Astronomers smooth this out with a fictitious mean Sun, giving the mean solar day, and the day in the SI sense is fixed at exactly 86,400 seconds. Reality has drifted slightly: the mean solar day has recently averaged about 86,400.002 seconds, and tidal drag from the Moon is lengthening it by about 2 milliseconds per century. That is why 27 leap seconds were added to UTC between 1972 and 2022. One rotation measured against the distant stars is shorter, about 23 hours 56 minutes 4.09 seconds, and a year contains one more of these sidereal days than solar days.

1 day = 86,400 seconds (exactly).

Sources: Wikipedia: Day; BIPM: SI Brochure, 9th edition

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