How accurate is the Mayan's Calender?

The Mayan people used many calendars. In their most common calendar (the one they would have stuck to the fridge... if they had fridges), New Year's Day fell on the day of what we call the December solstice.

The Mayan calendar that is used in the Big 2012 Hoax is the one called the Mesoamerican Long Count calendar.

It is simply a day-count calendar

Today's date = 1 + yesterday's date.

As such it is very accurate when it comes to calculating the number of days between two dates. If you note the date on one day, then you look at the calendar exactly 1,000 days later... the new date will be the old number + 1000.

Even modern astronomers use something similar.

It is good when you want to study periods that stretch over very long periods (close to a century for example).

Other than that, the calendar is not useful.

The Mayans used a system that is not base-10 (our system is base-10: after the last digit has gone from 0 to 9, the next digit increases by 1 and the last digit goes back to zero).

In the Mayan calendar numbering scheme, the last digit goes from 0 to 19 (it is base-20). The second digit from the end goes up from 0 to 17 (it is base 18). This gives them "years" of 360 days.

The Mayans knew that the year was really around 365 and a quarter days (and this was reflected in the long-term average of their common calendar -- the one on the fridge). However, for calculations, 360 is such a convenient number (it can be divided by 2, 3, 4, 5, 6, 8, 9, 10, 12...). This was very useful for a people who did not use fractions.

The rest of the columns (counting the "years") are all base-20.

So, around December 21, according to the count as given by José (the guy who invented the lie about the Mayan calendar ending and the myth about the "great accuracy of the calendar and its predictions"), the Long Count calendar should reach a round figure.

12.19.19.17.19 will be followed by 13.00.00.00.00, which will be followed by 13.00.00.00.01 and so on.

However, this was based on a count that was guessed at from whatever little info we have. Recent discoveries seem to indicate that the count might be off by decades.

The present count (if one could go back to day number 00.00.00.00.00) would have started 5125 yewars ago. However, we know that it did not.

It is a bit like the AD calendar that we now use, where the calculations were done in what we now call the 6th century and the calendar itself was adopted around the year we now call AD 800 (i.e., someone calculated the year where Jesus Christ was deemed to have been born, and that year was called year 1).

The Mayan calendar would have been put in place (at least, for the Mayans) roughly 1500 years ago.

A calendar doesn't have anything to do with time of day. It's only a way of counting days. A calendar can't really be said to have some kind of inherent accuracy. It is simply a defined system for counting days and longer time periods made up of days. The real question is whether or not we've accurately identified how the Mayan calendar maps to the Gregorian calendar the world currently uses. That isn't based on any property inherent to the Mayan calendar, but rather to our ability to line up the dates based on historical documents and information.

Anyway, there's nothing special about the Mayan calendar, unless you have an anthropological interest in such things. For most people, there's nothing to get excited about.

While they were wonderful naked eye astronomers, and created a remarkable calendar, it was not terribly accurate if by accurate, you mean did it keep the calendar in sync with the Solar year? They used a year of 365 days, and the year is actually 365 and about a quarter days long, which is why we have a leap year every four years. So the Mayan calendar fell a day behind every four years, or about a month per century.

As a codicil, they probably knew the year was about 365 1/4 days long, they'd calculated the Venusian year to a fraction of a day, but didn't feel it was necessary to incorporate into their calendar.

The Mayans had a 260 day religious calendar and a 365 day seasonal calendar, so the seasonal calendar was off by 1 day in 4 years.

The Long Count, which is what people are usually referring to when they talk about the Mayan Calendar, is simply a count of days in periods of 18s and 20s starting from a date sufficiently far back in time before their civilisation and allowing dates over a wide time span to be expressed unambiguously. It's start date is estimated to be August 11th, 3114 BCE.

A count of days is not related to any natural cycle, so it's not meaningful to talk about its accuracy. Day 2 follows Day 1. Who's to say whether or not that's accurate?

Ignore any claims about the 'great accuracy' of the Mayan calendar. These are made by the cranks trying to attribute some sort of doomsday prediction to the Mayans. One of their ploys is to make out that the Mayans were some sort of super race with a more accurate calendar than we have today. The Mayans made no doomsday prediction and any talk of a highly accurate calendar is nonsense.

A lot more accurate than the one you get from your local hardware store, bank or insurance company every year.

It has absolute precision.

One day in their calendar = one day in ours.

You can not get any more accurate than that.

But having an accurate calendar did not prevent the Spanish from subjugating them.

It's off a fraction of a second per day