How Long Is a Decade And a Century?

How long is a decade and a century?


a decade is measure of 10 years
a century is a measure of 100 years
you also got a lustrum, a measure of 5 years
and a ‘jubilee’ is 50 years
and a score is 20 years
the 2 weirdos is
(1) a generation, which is the amount of time it takes to replace yourself in the great scheme of things, and by the time most folks is 25 years old, they’ve already managed to produce at least one unit that’ll survive to ‘take over the family business’ by the time THAT one jumps the ‘generation gap’ of ITS ’25 years’.

(2) a lifetime which has been established as ‘3 score and 10’, (3x20)+10, 60+10=70 years of ‘useful productivity’ ‘mean time before failure’, which, in more than 6000 years of development, is STILL valid when you use the same baseline, as are the NOTEWORTHY clusters and individuals that make it beyond the century mark.

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It all depends on the calendar that we choose to use.

There are societies that use the Gregorian (majority) and others that use the Julian calendar.

There are also others that use the 13 moon calendar.

All these calendars will create a difference in when months end and begin.

In Russia for example, it is not Christmas until January 7th when the rest of the world has already marked Christmas. This is because of the Julian calendar that the faithful there use. Faithful means Catholics.

So is it always a fact that a decade has 10 years and a century 100 year

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How long is a century?

A century is a time of 100 years. Hundreds of years are numbered ordinally in English and numerous different dialects. The word century comes from the Latin centum, which means 100.

How Long is a Decade and Why?

Decade turned into a piece of the English jargon in 1590 formally. It is essentially used to allude to like clockwork in a century. For example, the 1680s or 1930s, which means the time between 1680-1689.

In the Georgian schedule, many years signify various periods. Their schedule has no zero implying that in the event that you are referencing the 1850s, it is the period between 1851-1860.

The contrast between the Georgian schedule and the standard schedule is seen while deciding explicitly a very long time in a century. For example, normally, the eighties allude to the years between 1980-1989. However, in the Georgian schedule, the 190th decade is between 1981-1990.

The use of decade to represent ten years duration has empowered humankind to separate huge chronicled occasions without any problem. Many years have permitted people to rapidly recognize explicit past occasions, for instance, the 40s or 30s, which implies the 1940s and 1930s, separately.

Name of the period Number of Years it covers Someone in their
Denarian 10-19
Vicenarian 20-29 The 20s
Tricenarian 30-39 The 30s
Quadragenarian 40-49 The 40s
Quinquagenarian 50-59 The 50s
Sexagenarian 60-69 The 60s
Septuagenarian 70-79 The 70s
Octogenarian 80-89 The 80s
Nonagenarian 90-99 The 90s
Centenarian 100 and above

Other terms used in the calendar

Century, which is a time of a hundred years, for instance, the nineteenth century. The nineteenth-century denotes the years between 1901-2000. A period going on for a very long time is a bicentennial.

  • Thousand years, it is utilized to term 1000 years.

  • Megaannum, it is utilized to portray 1,000,000 years.

  • A time of about fourteen days is a fortnight

  • A score is 20 years, while a lustrum is for a very long time.

  • A limited ability to focus 2, 3, or 4 years gets named as a biennium, triennium, and quadrennium, individually.

Why is Decade 10 Years Long?

The word decade is from the Greek word ‘dekas,’ which means a gathering often. The word decade was utilized by the Romans, who utilized the syllable dec-to distinguish things assembled in tens: E.G., decathlon, decagon. The two terms depict an assortment of ten things. The word dec-was, thusly, consolidated into the schedule to show the circumstance of 10 years.

What is a Century?

People need to recognize approximately that how lengthy is a century? A century equaled to a hundred years. The century way that it is an arbitrary length of 100 years. There are viewpoints and requirements of centuries. One view primarily based at the on the strict structures and the opposite hand the second one standard based totally on the overall usage (popular perspective). In these perspectives, humans gets the exact idea of ways lengthy is a century with different thoughts and concepts. With strict construction in the 1st-century begin with the 1 AD and its ends with a hundred AD. The related pattern goes with the identical order in onward.

How long is a century?

Besides, to know approximately the century decade, human beings won’t get the suitable solution about how lengthy is a century? In this text, we tricky all the associated information about a century, its periods and decade period. In the representation of one hundred years, we might say that a century cited a motorcycle experience of a hundred miles. But in case you are taken this assumption in metric centuries than the consequences are different from this assumption. This is because the metric centuries are shorter than the preceding century. Let we give an explanation for this with the use of the identical instance that if you are taking one hundred years, then the metric century may be stated the bike ride of 100-kilometers. These each conditions can be considered by way of the different relative cycles of the single day. The majority taken those effects for granted however a few human beings thoroughly conclude all the findings to discover the precise solution of ways long is a century.

Calculating the time

In between the nation of hours in the saddle, the length relies upon on some factors which are accessible in our environment. With the previous example, the resulted time relies upon on these elements which encompass wind direction, the pace of the wind, Cyclist strength, and different factors. It mentioned that a century is passing explicitly in one 2d at a time of expansion. Some of the mathematicians file that few of us lives this entire trip in a bit time which is much less about to the calculated results. The resultants output equals to 3.16 billion seconds in one go.

Centenial Year

In the preceding strict construction model, the ninth century will start on the year calculated with formula (100 x n) – 99 and it ends with (one hundred x n). Due to this purpose the century can simplest include one yr . This 12 months is referred to as the centennial 12 months . The centennial 12 months starts offevolved with every century range . In the second general which is known as standard usage, the centuries associated with the decades. This alignment is formed by way of grouping many years by way of digits. In this 2d model, the 9th century will begin with the year calculated with formula (one hundred x n) – 100 , and it ends with a hundred x n) – 1. The outgoing results display like odometer effects. The first century begins with the year number zero in place of starting with one year .

How long is a decade and a century? To answer this question first we have to know what actually a decade and a century is.

So, decade is a period or series of ten years. The word decade is a French and Latin word, which is derived from ancient Greek word “dekas”, which means “a group f ten”. There are 120 months and 3650 days in a decade. 20s is the current decade according to the Gregorian calendar. On January 1, 2020, people welcomed the new decade “20s”. It is the third decade of the 21st century, which will end on December 31st 2029 and the new decade “30s” will start.

A century is a period or group of one hundred years. The word century comes from Latin word “centum” which means “one hundred”. It is abbreviated as c. There are 10 decades in a century. Century is referred as a period of 100 years which are counted from the assumed year of the birth of Jesus Christ. According to the Gregorian calendar, the 1st century was from the year 1 to 100; there was no year “zero”. The 2nd century included the years from 101to 200 and this goes on, and now we are living in 21st century. The twenty first century began on January 1, 2001 and it will end on December 31, 2100.

Hence, both decade and century usually refer to the groupings of calendar years.

HOW LONG IS A MILLENNIUM? Millennium is equivalent to “one thousand” years. Sometimes, it is known as the “kiloannum (ka)” or “kiloyear (ky)”. Millennium word derives from the Latin word “mille” which means thousand, annus or year. According to the Gregorian calendar, the first millennium was celebrated on the beginning of year 1 which goes on till the end of the year 1000. The second millennium was from year 1001 till the year 2000, and then the third millennium in which we are living, which began from January 1, 2001 and it will end on December 31, 3000. To welcome the third millennium, people enjoyed the celebrations at the midnight between December 31, 1999 and January 1, 2000. There are 100 decades and 10 centuries in a millennium.

AGE BY DECADE: There are various words for the people in each decade of age. These prefixes used in such terms are always from the Latin.

  • Denarian is the one whose age is between 10 and 19.

  • Vicenarian: a person whose age ranges from twenty to twenty nine; someone in his or her 20s. Word vicenarian is originated from Latin word “vicenarius” which means “of or containing twenty”.

  • Tricenarian is someone whose age lies in between thirties, which is thirty to thirty nine years.

  • Quadragenarian is a person with in the age of 40 to 49, or someone in his/ her forties (40s).

  • A person who is in his 50s (age 50 to 59) is known as Quinquagenarian.

  • Sexagenarian: a person whose age is between 60 and 69, inclusive; someone in their 60s.

  • Septuagenarian is a person whose age is between 70 and 79; someone in his or her 70s. Septuageni is the Latin word which means seventy.

  • A person in his 80s, which means his or her age rages from 80 to 89, is called as octogenarian.

  • Nonagenarian is someone in his/ her 90s that is in between 90 to 99.

  • Centenarian is a person who has reached the age of 100 years. He is called centenarian till the age of 109.

  • Supercentarian is a person with the age of 110 or older (no upper age limit is defined). This term was coined in 1991. There are only a few people who have lived to age 115.

WHEN DID YEAR 1 START? The terms “Anno Domini (AD)” and “Before Christ (BC)” are used to number years in both the Julian and Gregorian calendars. The term Anno Domini is the Medieval Latin, which means “in the year of our Lord”. AD 1 was the first year of Christian/ Common Era (CE) of the first millennium and first century. The year was started on Monday according to the proleptic Gregorian calendar, while it was started on Saturday by the proleptic Julian calendar. There is no year “0” in the system of year counting, so the year AD 1 follows the year 1 BC. 1 BC means the year before Christ was born. It has since been determined that Christ was born prior to AD 1.

The term decade became part of the English vocabulary in 1590 officially. It is significantly used to refer to every ten years in a century. For example, the 1680s, this denotes the time between 1680-1689. In the Georgian calendar, decades indicate different periods. The difference between the Georgian calendar and the standard calendar appears while determining a specific decade in a century.

How long is a Decade?

The use of term decades symbolizes a ten years period. It makes it possible for humanity to distinguish major historical events easily. Decades allow human beings to identify specific past events quickly, for example, when we speak 40s or 30s, it means the 1940s and 1930s, respectively.

Naming the Decades

Every decade has derived a nickname from significant events that occurred during that period. One example in US history is the ‘roaring twenties,’ which implies the period in the 1920s. During this period many cultural changes and economic growth took place. The term decade is used to identify the period when Japan’s economic market collapsed in the 1990s. The period was recognized as the lost decade, just after the Second World War. The crisis persisted for almost a decade, and presently, it still affects the Japan business market.

Significance of a Decade

Almost all historical incidents are divided in decades; this makes it easier for people distinguish events occurring in a specific time during the past. In addition to the historical events, age can also be classified into decades.

Why is Decade 10 Years Long?

The word decade is taken from the Greek word ‘dekas,’ that means a group of ten. The word decade was previously used by the Romans, who used the prefix dec- to identify items grouped in tens: For example decagon or decathlon. The two terms express a collection of ten things. This word dec- was, then, incorporated into the calendar showing the timing of 10 years.

How Long is a Century

Century is a period of a hundred years, for example, the 19th or 20th century. The 19th century includes the years between 1901-2000. Whereas a period lasting for 200 years is a bicentennial.

Start and end of centuries

Although a century spans an arbitrary period of 100 years, there are two points of view on the character of standard centuries. One based on strict construction, whereas the other based on popular perception.

According to the first point of view, the 1st century AD began from 1 AD and ended with 100 AD, while the same model continues onward. In this model, the *n-*th century starts with the year ending with “01”, and ends with the year ending with “00”. For this reason, a century only includes one year, that is the centennial year, that starts with the century’s number for example 1900 was the last year of the 19th century.

According to a popular observation and practice, centuries are frequently structured by grouping years on the basis of their shared digits. According to this model, the nth century starts with the year ending in “00”, and ends with the year that ends in “99”. For example, the 20th century is regarded as from 1900 to 1999, complete.

Other Terms for Different Time Durations

  • Millennium, is used to express 1000 years.
  • Megaannum, is used to describe one million years.
  • A period of 2 weeks is called a fortnight
  • A score refers to 20 years, while a lustrum is used for five years.
  • A short span of 2, 3, or 4 years are given terms as a biennium, triennium, and quadrennium, respectively.

A century is the 100 year . “Centuries” or “Centenary” redirect here for the other uses, see Century (disambiguation), Centuries (disambiguation), or Centenary (disambiguation). the century is the time of the 100 year .

Centuries are numbered ordinals within English or many other languages. The word century comes from the the Latin centum, meaning one hundred. Century is the sometimes abbreviated as c. the centenary is the the hundredth anniversary, or the celebration of the that , typically the remembrance of the an event which took place the hundred year earlier.

Although the century may mean any arbitrary time of the one 00 year , there are two viewpoints on the the nature of the standard centuries. One is the based on the strict construction, while the other is the based on the popular perception. According to the the strict construction, the one st century AD began with the one AD or ended with the one 00 AD, with the the same pattern continuing onward.

within that model, the n-th century begin s with the the year that ends with the “01”, or ends with the the year that ends with the “00”. Because of the that , the century will only include one year, the centennial year, that begin s with the the century’s number (e.g. one 900 was the last year of the the one 9th century). within popular perception or practice, centuries are aligned with the decennial s by grouping year based on the their shared digits.

within that model, the ‘n’ -th century begin s with the the year that ends within “00”, or ends with the the year ending within “99”. For the example, the 20th century would be regarded as from the one 900 to the one 999, inclusive. that is the sometimes known as the odometer effect. The astronomical year numbering or ISO 8601 systems both contain the year zero, so the first century begins with the the year zero, rather than the year one. Millennium, the time of the one ,000 year .

The Gregorian calendar, put forth within one 582 or subsequently adopted by most countries, did not include the year 0 within the transition from the bc ( year before Christ) to the ad (those since his birth). Thus, the one st millennium is the defined as spanning year one –1000 or the 2nd the year 1001–2000. the time of the fifty year is the called semi-centennial, alternatively, if the time of the 10 year is the called the decennium , then fifty year could be called five decennium s, It is the also half the century. the decennium is the the time of the one 0 year .

The word is the derived (via French or Latin) from the the Ancient Greek: Romanized: dukes, which means the group of the 10 . decennium s may describe any 10 -year time , such as those of the the person’s life, or refer to the specific groupings of the calendar year . Duo decennial word may be used as alternatively for the the gap once within one 2 year .

Once beyond millennia we use numbers of the year such as "One Hundred-Thousand year ", or some use metric prefixes to the ‘annum’ (for example megaannum as referenced within Wikipedia) but they are basically the same idea. It’s the year 2100, or we’re at the dawn of the the 22nd century. Yep, that’s what’s coming next: the 22nd century. or as we all know, we’re currently within the 21st century, but the year begin with the 20. or within the 20th century, they all begin ed with the one 9, or within the one 9th, with the one 8, or so on.

the sexagenarian is the somebody within their 60s (60 to the 69 year old), or somebody who is the 60 year old. Sexagenarian may also be used as an adjective to the describe somebody within their 60s, as within our audience is the mostly made up of the sexagenarian women, or things related to the such the person, as within I have entered my sexagenarian year . the quadragenarian is the somebody within their 40s (40 to the 49 year old), or somebody who is the 40 year old. Quadragenarian may also be used as an adjective to the describe somebody within their 40s, as within I never thought I’d be the quadragenarian grandmother, or things related to the such the person, as within I have entered my quadragenarian year .

within the recent Yogi survey, 64% of the Americans said the next decennium will begin on the Jan. one , 2020, or end on the Dec. 31, 2029. or besides, they add, the definition of the the decennium is the just any one 0-year span. for the the decennium to the begin, we must begin with the the year ending with the one (2021) or finish with the one 0, or so far as chronology is the concerned, the year ending within 0 (2030). for the example, January one , 2001, opened the 21st century or the begin of the the new millennium, just as the year one A.D. So, 2010 to the 2019; 2020 to the 2029. However, today’s Gregorian calendar counts decennium s begin ing with the the first year one CE.

As discussed above, the Gregorian calendar goes from the one BCE to the one CE; there is the no year zero. within that case, 2021 is the technically the begin of the the new decennium . Some people consider the 75th birthday the “diamond jubilee.” that is the the term that used to the be used to the describe the 75th anniversary.

75 year of the life is the the milestone birthday, often referred to the as the platinum celebration. decennium may be used to the indicate the group of the 10 days within the sentence like “the first decennium of the the month”, but “the first 10 days of the the month” is the the expression more commonly used: the group, set, or series of the 10 . Most things quadrennial occur every four year (that’s the more common use).

We may say, for the example, that the U.S. presidential election is the the quadrennial event. But we may also say that president’s term within office is the quadrennial, making good use of the the "lasting four year " sense. The 21st (twenty-first) century is the the current century within the Anno Domini era or Common Era, within accordance with the the Gregorian calendar. It began on the January one , 2001, or will end on the December 31, 2100.

within contemporary history, the third millennium of the the anno Domini or Common Era within the Gregorian calendar is the the current millennium spanning the year 2001 to the 3000 (21st to the 30th centuries). When Did the 21st Century begin ? on the January one , 2000, humankind celebrated the beginning of the the new millennium—which was one year too early.

How long is a decade and century? A decade is simply 10 years long and the century is 100 years long.

The term derives from the Ancient Greek:, romanized: dekas, which means a ten-person group (via French and Latin). Decades may apply to particular groups of calendar years or every ten-year span, such as those of a person’s life.

Why is it 10 years?

The prefix dec- was widely used by the Romans to denote sets of ten objects, such as a decathlon, which is a set of ten athletic challenges, or a decagon, which is a standard 10-sided polygon. The century (100 years) and the millennium (1000 years) are two other time units derived from Latin (1000 years).


  1. A “decade” is characterised as a span of ten years.

For example, Mozart discovered chromatic harmony in his final decade, which was a degree which was very rare in those timings, so simply it referred to his existence in his final 10 years no matter which of the calendar years are contained.

  1. Another thing is that the first day of a person’s life starts at the day he is born and it concludes when he is aged 10 years old.

  2. The second decade of life begins on their 11th year of life (during which one is commonly referred to as 10) and ends on their 20th birthday at the end of their 20th year of life and so on. The tens digit of their age is used to characterise following decades of life in a similar way.

  3. Decennial is an event which returns each decade.

Calculating the decade

There are two ways in which decade can be calculated.

One opinion or formula for calculating the decade is that the start of the decade should be calculated where a year end is 0 for example 1890 is the start of the decade but the decade end should be the year where it ends with the number 9.

As such it is 1980 to 1989. Likewise, 20th centuries’s 2020 of 21st century.


If we break down various groups of different time sets into multiple subsets we get the following results.

  • How many months in a decade?
    There are 120 months in a decade.

  • How many days in a decade?
    There are 3650 days in a decade.

  • How many hours in a decade?
    There are 87,600 hours in a decade.

  • How many decades are in a century?
    There are 10 decades in a century.

  • How many decades are in a millennium?
    There are 100 decades in a millennium.

How long is a Century?

  1. A century is a 100-year era. In English and many other languages, centuries are counted sequentially.

  2. The term century is derived from the Latin word centum, which means “one hundred.” c is a popular abbreviation for century.

The 1st Century

According to the Julian calendar, the first century ran from AD 1 to AD 100. To differentiate it from the preceding 1st century BC (or BCE), it is sometimes written as the 1st century AD[1] or 1st century CE.

The Classical era, age, or historical time includes the first century.

Determination of century

  1. A century may be any 100-year duration, but Pope Gregory XIII established the agreed calendar century in 1582.

  2. His affirmation of ‘Anno Domini’, also known as the Gregorian calendar, references Jesus’ life as the basis of our calendar period.

  3. Our modern definition of a century from the birth of Jesus is year 1, as established by Pope Gregory XIII’s ‘bull’ (document), however, the years 1 to 100 were designated as the time of Jesus, while the years 101 and on were designated as the years after Jesus.

  4. Since ‘Anno Domini’ means ‘in the year of our Lord’ (meaning after Jesus’ time on earth), 2009 is the first year of the twenty-first century.

Calculating the Century

There is a formula available by which you can calculate the century.


First century starts from the following date.

January, 1st day of year, year 1

And it ends on December, 31st day of December, year 100

Likewise, for the 2nd century we take 101 as the start of the second century and 200 as the end of the second century.

Start of 21st century is on 1st Jan 2001 which has end on 31st Dec 2100. 2020 belongs to the 21st century.

## How many years are in decade, century and Millennium?

According to the Gregorian Calendar, we can formulate timelines into the years.

  1. 1 millennium is equal to 10 centuries and 10 centuries is equal to 1000 years.

  2. 1 century is equal to 10 decades and 10 decades is equal to 100 years.

  3. 1 decade is equal to 10 years and 10 years is equal to 3652 days.

Years into biennium, lustrum, decade, century and millennium

Let us check the following as well.

  • 2 years = 1 biennium

  • 5 years = 1 lustrum

  • 10 years = 1 decade

  • 100 years = 1 century

  • 1000 years = 1 millennium

Bottom Line

Decade means a span of ten years.century means a span of 100 years. We also have formulas available to calculate any decade and century.