How to Write the Century
Summary
Write centuries in either numerals or words. Names of specific centuries are spelled out in some styles and written in figures in others. Single-digit centuries are generally spelled out.
- the 1800s
- the nineteenth century or the 19th century
- the sixth century
Don’t set the letters denoting ordinals in superscript.
- the 21st century, not the 21st century
An apostrophe before the s in names of centuries is unnecessary, but not incorrect.
- the 1600s or the 1600’s
Avoid capitalizing names of centuries.
- the twentieth century, not the Twentieth century
What years make a century?
A century is a period of 100 years. A specific century begins with year 01: the twentieth century began in 1901 and ended at the end of the year 2000, the twenty-first century began in 2001, and so on. Centuries may be written in various styles: in numerals, words, or a combination of both, and with an apostrophe or without.
- Medical science progressed by gigantic leaps and bounds in the twentieth century.
- The 1800s saw the advent of globalization.
- Anita has written a paper on maritime trade in the 1600’s.
- One of the great discoveries of the 21st century has been the existence of gravitational waves.
The first century ran from year 1 to year 100, so each new century begins from a year ending in 01. Thus, the twenty-first century officially began on January 1, 2001. However, in popular usage, a new century is often thought to begin in the year the digits change—for example, when the year changed from 1999 to 2000.
Use of BC, AD, BCE, and CE
The abbreviations BCE (“before the Common Era”) and CE (“of the Common Era) or BC (“before Christ”) and AD (anno Domini) to denote the era may be used with centuries, though they are more often used to show the exact year. No comma is needed before the abbreviation. The abbreviations themselves generally don’t contain periods.
- In the 13th century AD, Genghis Khan began his conquest of the world.
- Alexander the Great lived and died in the fourth century BCE.
BCE and CE are alternatives to BC and AD. The two systems are numerically equivalent.
1800s or 19th century?
Both forms of usage are correct: “the 1800s” and “the 19th (or nineteenth) century.” Since the years of the nineteenth century begin with the numerals “18,” it is also called the “1800s” (pronounced eighteen hundreds). No apostrophe is necessary before the s.
- The 1800s was a time of industrialization.
orThe 19th century was a time of industrialization.
- The Renaissance began in Italy in the 1300s.
orThe Renaissance began in Italy in the fourteenth century.
Centuries written in numerals—e.g., “the 1600s”—may be either singular or plural (the 1600s was or were), depending on context and preference.
Terms like “1900s” and “2000s” can also mean the first decade of a century (e.g., 2000s, 2010s, 2020s). Context usually makes it clear whether you are referring to the century or the decade. If confusion is possible, prefer to clarify: “the 20th century,” instead of “the 1900s.”
Use of apostrophe
An apostrophe before the s in the name of a century is unnecessary (though not incorrect) and generally omitted in formal writing.
- The 1600s marked the end of the Middle Ages in Europe.
1600’s is not incorrect but unnecessary.
- The 1700s saw a revival of literature in England.
- Industrialization in the 1800s affected different regions of the world differently.
Most style guides, like the AP Stylebook, the Chicago Manual of Style, and the APA Publication Manual, advise against using an apostrophe in plural words, except when not using one would cause confusion.
Words vs. numerals
Centuries may be written in either words or numerals. Note however that in formal writing, single-digit centuries (e.g., the ninth century) are generally spelled out instead of being written in figures. Double-digit centuries may be written either way (e.g., the 21st or the twenty-first century).
- Just like us, people of the seventh century believed they lived in modern times.
- Since the 19th/nineteenth century, humans have relied on science to extend their life spans.
Always use words instead of numerals for names of centuries at the start of a sentence. (Numerals are generally not used to begin a sentence.)
- Poor: 17th-century playwrights like Shakespeare and Beaumont are still studied in schools.
Better: Seventeenth-century playwrights like Shakespeare and Beaumont are still studied in schools.
Chicago vs. AP style
The Chicago Manual of Style suggests spelling out the number denoting the century, while the AP Stylebook recommends words for numbers up to 10, and numerals thereafter.
- Chicago: The twentieth century ushered in the digital age.
AP: The 20th century ushered in the digital age.For two-digit centuries, use words in Chicago style but numerals in AP style. - Chicago, AP: Her paper discusses the role of doctors as diplomats in the sixth century AD.
Spell out single-digit centuries in both Chicago and AP styles.
Style guides differ in their recommendations on whether to use numerals or words for the name of a century. Wikipedia, for instance, uses numerals for all centuries.
Whether to use numerals or words is a matter of style rather than grammar. Which style you use can depend on your field of study or the style manual followed by your university or publication. Make sure to follow a consistent style throughout your document. As an editor, respect the writer’s preference.
Superscript for ordinal numbers
Since centuries occur in chronological sequence, they are written as ordinal numbers. When using numerals, avoid using superscript for letters that denote the ordinal (st, nd, rd, th).
- Poor: Because of mass vaccination programs, child mortality rates fell significantly in the 20th century.
Better: Because of mass vaccination programs, child mortality rates fell significantly in the 20th century. - Poor: This book discusses issues of privacy in the 21st century.
Better: This book discusses issues of privacy in the 21st century.
Most style guides recommend against using superscript for ordinal numbers, since it can affect readability across fonts and typefaces.
Use of hyphen
Use a hyphen to show two-digit numbers in names of centuries from the twenty-first century onward.
-
Poor: The twenty first century hasn’t yet brought the flying cars promised to us by science fiction.
Better: The twenty-first century hasn’t yet brought the flying cars promised to us by science fiction.
Hyphenate two-digit numbers for clarity (ninety-nine cupcakes, one hundred seventy-five muffins).
Don’t unnecessarily place a hyphen between the number and the word century.
- Incorrect: the twenty-first-century
Correct: the twenty-first century
Capitalization
Don’t capitalize the names of centuries, unless part of a proper noun or a title.
- Incorrect: Her new historical novel is set in the Eighteenth century.
Correct: Her new historical novel is set in the eighteenth century. - Incorrect: The East India Company was involved in the slave trade of the Sixteenth and Seventeenth Centuries.
Correct: The East India Company was involved in the slave trade of the sixteenth and seventeenth centuries.
Of course, in proper nouns, capitalize as needed.
- Twentieth Century Fox
Also capitalize major words in book titles.
- The Nineteenth-Century Guide to Baking
Two or more centuries: Singular or plural?
When referring to two or more centuries together, use the plural word centuries if the names of the centuries are joined by and or through. Use the singular word century if they are joined by to or or.
- The 17th, 18th, and 19th centuries shaped the postcolonial world of the 20th century.
- The medieval period lasted from the fifth through fifteenth centuries in Europe.
- Renaissance art of the 14th to the 16th century marks a clear break from medieval values.
- Did Jane Austen live and write in the 18th or the 19th century?