This page gives the definition of the Bible clock. It also explains why each time is displayed as it is and develops a model clock for use with prophecy.


Greenwich Mean Time (GMT) is the time system used within most computers to measure time. It is an international standard used in astronomy and is also the typical time base used for setting local times in time zones around the world. The following is the current GMT:

Here is current GMT:

GMT has no concept of Daylight Savings, so all days measured using GMT are also 24 hours long.

Local Time

Each location around the world has a standard time zone, defined by local law, that determines the time of day in that location. These times are usually, but not always, whole numbers of hours from GMT.

Local times also usually have a notion of Daylight Savings. This means the number of hours from GMT can differ throughout the year. This also means that day lengths can be 24, 25 or 23 hours long. These odd length days are usually ignored, only 2 days per year are not 24 hours long, but they do occur.

Because the local concept of date usually changes at midnight, local time, the day, month and even year can differ from the day, month and year observed at Greenwich.

Here is current Local time:

Other Local Times

Cities around the world have different times based on their local laws. The following are a representative sample of times from various places around the world. The times are current.

Scan down the list and note Calcutta, Katmandu and Iran. These are not even whole hours from GMT. This is an example of how local jurisdictions change their local time.

Local Time in Jerusalem

Jerusalem’s clocks are set based on the time zone in Israel. Modern Israeli law establishes the timing for Daylight Savings and it is a whole number of hours from Greenwich. This is the time used by nearly everyone living in Jerusalem.

The following is modern, current, local time in Jerusalem:

Temple Mount Mean Time

The use of Greenwich as the standard point for setting all clocks around the world was established at the International Meridian Conference, held in Washington DC, in 1884. This conference selected the observatory at Greenwich as the location for the Prime Meridian.

Competing locations for the "zero point" for measuring the planet and thus setting the world’s clocks, included the Great Pyramid at Giza and Temple Mount in Jerusalem. But, because Britain was the world super power of the day, and because the British empire stretched around the world, the British were given the honor of setting the time. The use of Greenwich as the place for setting British railroad clocks was now extended to measuring distance and setting time across the rest of the modern world.

The problem with Greenwich for measuring time for prophetic purposes is that Temple Mount is the Bible’s mandated place for all earthly time keeping activity. A clock set to tell time at Temple Mount in Jerusalem is not a whole number of hours away from Greenwich because Temple Mount is not exactly 1/24th of the way around the world from Greenwich.

The use of Greenwich, though quite able to keep trains from colliding and planes on schedule, is not a place for measuring prophetic time world wide.

If you set a modern clock in Jerusalem the same way that a modern clock is set at Greenwich, and did not observe any Daylight Savings, then you would be setting a clock to what is technically called Temple Mount Mean Time. This is the first step in getting a proper prophetic clock.

This is done by effectively moving the clock at Greenwich to Temple Mount in Jerusalem. Since Greenwich is the "zero point" for latitude, an accurate map location of Temple Mount is all that is needed in order to know how far to shift the time.

A search reveals that Temple Mount is located at:

  • Lat: 31:46:29N (31.7748)

  • Lon: 35:13:30E (35.2249)

The decimal representation of the Longitude is the number of degrees east from Greenwich. There are 360 degrees around the world, and 24 hours around the world, so converting from degrees to hours is done by dividing out the degrees and multiplying by the hours. Temple Mount is 35.2249/360 * 24 = 2.34832666667 hours east of Greenwich.

Since there are 60 minutes in an hour, the fractional part can be multiplied by 60 to compute the minutes: .348326667 * 60 = 20.8995996 Minutes and similarly .8995996 * 60 = 53.975976 Seconds. Or, stated simply: Temple Mount Mean Time is 02:20:53.9760 east, or earlier, of Greenwich Mean Time.

Internal computer clocks are based in seconds, so these same equations can be done based on seconds. This yields the correction needed from internal GMT time values to TMMT values. There are 24 * 60 * 60 = 86,400 seconds in a day. To compute seconds away from Greenwich, the equation is 35.2249 / 360 * 86400 = 8453.976 Seconds east, or earlier, than Greenwich Mean Time, for times based at Temple Mount Mean Time. (Rounded to the second, the correction is 8454 seconds.)

Current Temple Mount Mean Time:

Compare this with the current local time in Israel, which also includes the local time in Jerusalem.

Current modern clock time in Jerusalem:

These two times differ by the correction, and by the modern observation of Daylight Savings in Israel. During most times of the day these two values are off by the 20.8995996 minutes or by this and the Daylight Savings hour. (In the summer is when Daylight Time normally kicks in.)

Because the rest of the calendar date is based on the clock, the apparent difference can be much higher. The TMMT values move to a new hour about 20 minutes ahead of Israel’s legal time. That means the day of the month, the month of the year and even the year advance earlier than they do for the modern legal time observed in Israel.

Understanding Mean Time

The clock at Greenwich, and therefore the clock at Temple Mount, is based on the average time at that location around the solar year.

Individual daylight periods are longer, and shorter, than 24 hours. That variability in visible day length is being worked out by averaging the number of hours in the year.

Mean Time first became important with the use of mechanical clocks, since they naturally average out the time of day. Since we’re still using a computer to tell the time, the use of a mechanical average has some innate advantage. But, is this good enough?

The most important historical times, where we care about time to the hour or better, are those in Jesus’ Passion Week. That week was near the spring equinox, so an approximation to Mean Time as done here is very reasonable.

The tough question, though is this: Does the Bible intend readers to use a fixed length hour with 12 hours of daylight and 12 hours of night time? Or, does the Bible expect the length of the hour to change slightly through the seasons?

The answer to this is self-evident, once the use of hours as found in the Bible are understood.

All of the natural time measurements, hours, days, weeks, months, years, are prophetically mapped to each other. Anyone speaking, say, about hours, is also speaking about weeks, and therefore sets of 7 days.

Even 1000 years is mapped prophetically in the Bible to a 24 hour calendar day. This is in fact how to unpack Jesus’ parables related to hours.

Given these ratios, hour lengths would change only when, say, millennia change length too.

As far as we know, periods of time 1000 years long do not change length so neither does the 24 hours in a calendar day. If the day length is not changing, at all, then neither are the hours.

Use of Mean Time implies a time keeping system averaged around the year and this is what the Bible implies should be done.

Temple Mount Time with a Bible Time and Bible Date

Look again at the current Temple Mount Mean Time and consider the terms used to describe the time. Since you were old enough to tell time you have been familiar with these terms. You can probably read off each term and give the name for the term. Even if your country uses a different convention, you probably know the time well enough to be able to figure out the time simply by reading the time.

Current Temple Mount Mean Time:

The next question, though, for getting at prophetic time in Jerusalem is to ask if these are the right terms for describing dates and times in a fashion consistent with the prophetic texts of the Bible.

I dare say that none of the values of these terms is ready for use as a basis for measuring prophetic time. What remains is to cause this now accurate clock to tell time in a way that matches the text of the Bible.

For the various values of hours, days, months, years, the corrections involve the adoption of Biblical conventions for values you already know. Your instinctive understanding will still work, even if the values will be strange.

For Minutes and Seconds though, the best Biblical definitions are quite strange and instincts do not work.

Correct Bible Minutes And Bible Seconds

The purpose of Minutes and Seconds is to divide hours down into smaller units of meaningful time. The use of Modern Minutes comes from the parallax of the sun as it strikes a sundial. The sun is not a single, precise, point in the sky. It has width. That width causes shadows cast by the sun to be fuzzy. That fuzziness is 1 minute wide which is where the name and associated time value comes from. Seconds, are simply the "2nd" order application of the same concept to more accurately divide the minute.

As I was studying Jesus’ actions in Passion Week I came to realize that each of his hours that week was an exact prophetic match to 1 week in his ministry.

This strongly suggests that the proper division of hours into smaller units is not into 60, like we do now, but into 7 distinct minutes.

This is not instinctive at all, but the closest instinctive value is a modern 10 minute interval. From there your instinct should recognize the "10 minute break," or 1/6th of an hour, that happens so often in modern industrial situations is equivalent to a 1/7th of an hour Sabbath rest. This break time naturally comes at the end of hours, just as it does at the end of weeks.

It also became quite evident that the next subdivision of time matched Jesus’ prophetic days in his ministry. Each of those days was a prophetic match to 30 historical years. So, if Bible Minutes are divided into Bible Seconds of 30 units each, there is an exact, 1 for 1, prophetic match for Bible Seconds back to historical years.

This backward match is profoundly interesting since it reveals the base pattern for time repetition that we all live through, even if we don’t know it.

Let me state this slightly differently. If you break time up this way, into 1/7ths of hours for minutes and then into 1/30ths of those minutes for seconds, you are measuring time in the same units of time that Jesus used to structure His created universe. These are the same units of time he used to structure His life on earth.

This division of time is a reminder that He used this same time system to even structure your very life. This is the system he used to number your days. It is a reminder of His divine plan for His life, your life, and the lives of everyone else around you.

Statements and Conversions

Taking an hour and breaking it into 7 equal amounts leads to a system where each of the minutes is named by a number. Of course the number "zero" does not exist in Bible based counting systems, so the first 1/7 of an hour is known as Minute 1. The last is known as Minute 7. Similarly seconds are also named by a number, counting from 1 through 30.

The first Minute:Second pair within an hour is 1:01 and the last is 7:30.

This is the same way that days in weeks are counted, 1 through 7 and the same way that days in months are counted, 1 through 30. There should be no surprise here.

As a test, the last second of the first half of an hour is what?

OK, time’s up. The answer is: 4:15

This is very different than modern clocks that use real number systems and begin their first divisions with zero. 12:00:00 is a legal modern time, either noon or midnight, but it uses zeros. This use of zero to compose a time is unknown to Biblical based counting systems.

For comparison there are 60 * 60 = 3600 modern seconds in a hour while there are 7 * 30 = 210 bible seconds to the hour.

To convert the following equation can be used:
X MS / 3600 * 210 = Y BS

Typically, to avoid round off error in the computer, this equation would be reversed, as in X MS * 210 / 3600 = Y BS.

The following table shows some typical modern minute:second pairs and the equivalent Bible minute:second pairs. Notice how the larger Bible Minutes "cover" the smaller seconds. Notice how the middle of an hour sees the Bible Minutes changing at the same time as the seconds. Both are evenly divisible by 2, so this is the case. Note also the use of 1 based math.

Correct Bible Hours

Review again the current Temple Mount Mean Time:

Current Temple Mount Mean Time:

The smallest terms, minutes and seconds, can now be adjusted to a Bible based strategy. What about the larger terms? These also need correction. The term to take next in order is the Hour.

Modern hours count beginning at Midnight. On a 24 hour clock the first hour is labeled with a double zero, "00" and then followed by the minutes and seconds. The first second of a day is 00:00:00.

On a 12 hour clock the hour 12 is borrowed from the previous day and used to count out the time in the first hour of the day. So 12:00:00 is the first second of the day on a 12 hour clock.

Both of these times are in the middle of the night, not the time when the Bible begins a new day. The 1st hour of a Bible based day begins at Sunrise. Calendar dates, though, change at sunset. Hours are only used to count the 12 hours of day light. Watches, 3 hour intervals, are used to count the night. Since "watches" are very rarely used in Scripture, and since time does run linearly, we’re going to use a convention for marking Night Hours and Day Hours. The suffix "DH" marks a Day Hour on the Bible Clock, and "NH" marks night hour. So: 01:1:01 DH marks average sunrise time in Jerusalem. 01:1:01 NH marks average sunset in Jerusalem. The presence of the single digit for the minutes, and the DH and NH marks the end are the quick clues that this is a Bible Time.

Remember the definition of the Mean Time component of the clock discussed above? By definition, the 06:00:00 AM is the time of sunrise, on average, when a clock is accurately set to the local time. 06:00:00 PM (or 18:00:00 Hours on a 24 hour clock) is likewise the average sunset time when the clock has been set accurately.

What we did, in effect, when we brought the clock from Greenwich to Jerusalem based on the longitude of Temple Mount, is we brought a highly accurate average time clock and "tuned it" to the average sunrise and sunset times in Jerusalem at Temple Mount.

We actually showed how to get that accuracy to the millisecond if that were needed. If the clock in the computer is set electronically from a standards body, then the displayed times come out with that same millisecond accuracy.

Because of the definition of when new calendar days begin within the normal 24 hour day, the first Bible_Hour:Bible_Minute:Bible_Second in any given day is 01:1:01 NH and it happens at 06:00:00 PM on the TMMT clock used above.

Note how this brings stunning accuracy to our ability to measure prophetic time. Hopefully, this is more accurate than is used anywhere in the prophetic application of scripture.

The first hour of the day, as quoted in scripture, begins at sunrise, or 01:1:01 DH in any given day.

Note very carefully, for the modern hours on a 12 hour clock the Bible Time for that same hour is Off by 5 hours. This is not simply an inversion of the modern clock. This 5 hour interval is so commonly missed that even many modern English Bible translations do not properly footnote this difference in time. (Even one of the translations on this website has it wrong.)

The following table displays a few sample times on the modern and Bible time systems.

Another test. If you have been paying attention, you should be able to start thinking about Bible Time in a Bible way. The Bible references the darkness over the land at the time of Jesus’ crucifixion. The following is the text:

45From the sixth hour until the ninth hour darkness came over all the land. 46About the ninth hour Jesus cried out in a loud voice, "Eloi, Eloi, lama sabachthani?" -- which means, "My God, my God, why have you forsaken me?" Matthew 27:45-46
(Matthew 27:45-46 NIV)

Jerusalem Bible Time

Review again the current Temple Mount Mean Time:

Current Temple Mount Mean Time:

Even if you can’t do the math in your head, you should at least understand what should be happening to this time in order to get it to display in a fashion consistent with the Bible. The last terms, the Hour, Minute and Second, get converted as spelled out in the previous section.

It should also be obvious that the shift of the calendar day change from Midnight, the western convention, to Sunset, the Bible’s convention, causes the apparent date to change too. Indeed, this can change all of the bigger terms in the date. What day it is depends heavily on the clock and how that clock is set.

If the western calendar says it is just after 6:00 PM (18:00 Hours) then the day of the week is one low, and so is the day of the month. Occasionally, like the last day of the month, and the last month of the year, the month and perhaps even year are also badly stated.

This website spends considerable space dealing with the establishment of that calendar from Scripture, and the determination of the relation between current modern dates and the correct Biblical date. The Year, Month and Day from that system will replace the Year, Month and Day from the Gregorian calendar used in the table above.

The year number, month number, and day number of the month simply sit in place of the modern year, month and day. This is not hard to understand. Instincts also work with these years months and days, even though the values may be a little strange.

But, what about the day of the week?

Most people know the days of the week by the conventional day names. Sunday is the modern name given to the Bible’s concept of the 1st day of the week. Saturday is the 7th day. But, those days are defined starting at midnight. What to do?

The convention used here is to warn that a Bible definition is used by placing a ~ ahead of the day name ~Wed or ~Wednesday warns that this day name is like a modern Wednesday, but that it begins and ends 6 hours earlier than normal.

Current Temple Mount Mean Time:

Current Temple Mount Mean Time, in Bible Time:

Cross Check

There is an older software calendar conversion library that was developed in 1998 that is a reference for checking this work. That earlier library reports the current date on the various calendars as:

Note this is matches the TMMT date given above for Temple Mount, but that it lacks the precision for dealing with the 6 hours between sunset and midnight. For those hours the reports based on time of day are more accurate.

Full Clock Simulation

There is a full Bible Clock simulation running as a web app. The URL for the clock itself is...

Using options in your browser you can install it to your device, especially phones. Use the top right menu in that app to configure.

Setting Mechanical Clocks

The original write-up for this page was done in March of 2005, soon after the fundamental math was worked out.

In the summer of 2006 we built a few mechanical clocks to indicate time this way. We did so by changing the face on otherwise commercially available clocks. We sold a few at a farmer's market to see what people would think.

It was an interesting conversation piece, but we did not have any means to make them in volume, so we gave up making clocks.

In discussion with people at our booth the topic of setting an analog clock to the local mean time often came up often.

With hours measured from sunrise, and since sunrise varies day to day, especially far from the equator, how were clocks set?

The answer is woven into the reason why our modern clocks are no longer marked the same way as done in the Bible. Indeed, the change was only made after modern astronomers started buying clocks that measured hours from when they were set. That time? Noon.

Noon is an English word that is also the name for an ancient letter which was originally a seed. Just as seeds split into 2 parts when they germinate, so, too, does noon split the day into 2 equal parts.

To accurately set a clock the instrument must be adjusted each day at noon.

The noon hour is the start of the 7th hour of the day. By Biblical principles the 7th unit of time is a sabbath. The modern world holds a daily sabbath, and in English it is called lunch. In Spanish a siesta. The most important hour of the day is not sunrise, but the 7th hour, the Sabbath, what we call Lunch.

In the days before mechanical clocks, even back to the Temple era, the candles in the Temple were the time keeping devices. The were replaced at sunset and sunrise, but the time was set by trimming the wick at noon, the start of the mid-day Sabbath.

Noon is also invariant across seasons and topography. The very problem of fixed length hours melts under the understanding that the clock is set at noon, and not at sunrise, and the sun is always directly overhead at the same time each day regardless of the seasons.