Abbreviations for Years: How to Use BC, AD, BCE & CE Correctly

Historically speaking…

When even native speakers get a certain aspect of English mixed up, you can bet it’s tricky for English language learners to master. This is the case with writing and saying years. Why do we have more than one word to represent an era? Why don’t they have the same position in a sentence? How do we punctuate and capitalize these abbreviations? Let’s clear things up for our students (and possibly for ourselves).

1. Meaning

  • BC stands for “Before Christ” and represents the years before Christ was born
  • AD stands for “Anno Domini,” which is Latin for “the year of our Lord,” and represents the years after Christ was born
  • BCE stands for “Before Common Era,” “Before Christian Era,” or “Before Current Era” and represents the time before the last 2015 years (at the time this was written)
  • CE stands for “Common Era,” “Christian Era,” or “Current Era” and represents years 1–2015 (at the time this was written)

BC and BCE represent the same time frame, but with BCE, the religious aspect is removed. The same goes for AD and CE (the religious aspect is removed with CE).

2. Position

  • 300 BC
  • AD 2015
  • 300 BCE
  • 2015 CE

BC, BCE, and CE come after the year. Write or say 300 BC or 300 before Christ, 300 BCE or 300 before common era, and 2015 CE or 2015 common era. However, AD comes before the year, so write or say AD 2015 or anno Domini 2015. This is because anno Domini is Latin for the year of our Lord, and we always say the year of our Lord before the year (so the year of our Lord 2015).

Is 2015 AD ever correct? Many people (myself included) were taught that AD stood for after death (after the death of Christ). Some people do write or say AD after the year, but as this is technically incorrect, it is far better to write or say AD 2015.

3. Punctuation & Capitalization

Is it BC or B.C.? BCE or B.C.E.? Well, it depends on which style guide or dictionary you follow. Merriam-Webster Dictionary (American English) lists these entries with capital letters and no periods (e.g., BC), but notes that they are often punctuated and/or written in small capitals (e.g., B.C.). Oxford Dictionary (British English) and Oxford Canadian Dictionary (Canadian English) also list these entries with capital letters and no periods (e.g., BC) and notes they are often written in small capitals, but they don’t list periods as common usage.

A popular American style guide, The Chicago Manual of Style, has these entries in capital letters with no periods (e.g., BC). This is consistent with many other types of abbreviations that they list (e.g., US, UK, WA, etc.). In my role as an editor, I’ve noticed that there is definitely a movement away from unnecessary punctuation.


Show your students examples of these dates in a lesson and then go over the explanation above. Our Famous Places lesson on Nazca Lines includes BC and AD in the first paragraph of the reading. (In fact, editing this lesson for our new English App is what inspired this blog post!)


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Leave a Comment ↓

  1. Kelvin Greene says:

    Oct 30, 2018 at 10:05 am

    Hello Tanya Trusla. Very good article and very good answers to comments. But that website led you wrong about counting years across eras in your answer to Komal on Mar 07, 2018 at 6:23 pm.

    We know there was a year known as 1BC and a year known as AD1, but there wasn’t a year known as 0 between them right?

    However, from January 1, 1BC to December 31, AD1 is 2 years, not 1 year, right?

    So, if we are not using any particular months when giving dates, and we say, for instance: “He reigned from 7BC to AD8”, that will be assuming that his reign could have been from anytime in 7BC and ended anytime in 8AD right?

    Sorry, I know this is redundant, but to clarify, his reign begin and ended any time between January 1, 7BC to December 31, AD8 right?

    And if we ONLY give the BC year and the AD year we have to allow for the whole year of each date given.

    So from 7BC to AD8 would simply be 7 + 8 =15 total years and you do not subtract a year.

    The dates in our example include the years:

    7BC, 6BC, 5BC, 4BC, 3BC, 2BC, 1BC, AD1, AD2, AD3, AD4, AD5, AD6, AD7, AD8.

    Count them, it is 15 years.

    So, any calculations of dates when ONLY the years are given, without months, across the two eras is simply added together to calculate the total number of years.

    1000BC – AD200 is a total of 1200 years because 1000 + 200 = 1200. And no, 1 year should not be subtracted, because the dates, as given, include the whole year of 1000BC and the whole year of AD200.

    Not having a year 0 between them doesn’t mean you subtract a year.

    However, just to be clear. If months are given and the dates were, for instance:

    “He reigned from March 3, 7BC to March 12, AD8”.

    This particular calculation would require 1 year to be subtracted. That would be exactly 14 years, not 15, because we know the months and they are the same.

    • Tanya Trusler says:

      Nov 20, 2018 at 6:29 pm

      Hi Kelvin,

      Thanks for taking the time to explain all this! You almost made my head explode (math is not my strong suit), but I now see what you’re saying. It makes sense that we would count it differently if the months indicated a one-year span versus two whole, separate years. I hope that anyone looking on how to calculate the number of years with a BC–AD range will read the great advice in your post!

  2. Bonnie Headley says:

    Aug 29, 2018 at 2:22 am

    I am doing genealogy and a person was born in 28 BCE. I can’t figure it out. Can you help? Thanks Bonney

    • Tanya Trusler says:

      Sep 03, 2018 at 2:31 pm

      Hi, Bonnie. That’s 28 Before Common/Christian/Current Era, so 2018 + 28 means that person was born 2046 years ago.

  3. Lee Ginn says:

    Jul 03, 2018 at 7:47 am

    I’m reading a book titled A History – China by John Keay. There’s a reference (r. c. 977-c.957 BC). What does the small r. Stand for? Never seen this before.
    Thank you, Lee

    • Tanya Trusler says:

      Jul 05, 2018 at 1:14 pm

      Hi Lee,

      Good question! I haven’t seen “r.” used like that before either. My colleague looked up the actual book for context and saw that the “r.” was mentioned when referring to emperors and dynasties. The Chicago Manual of Style lists the possible meanings of “r.” as “right; recto; reigned” so we’re pretty sure that “r. c.” means “reigned around [those dates].” Hope that helps!

  4. lluis says:

    Jun 05, 2018 at 5:07 am

    Thank you for your explanation. I have a doubt regarding when is appropriate to use these abbreviations and when not?
    I mean, if we are writing about the date a building that was built in the twentieth century we would never use them. If we are writing about the date a building that was built in the Roman Empire we would surely use them. But, what if we are writing about the date a building built in the Reinassance. Should we use them or not?
    I would like to write: “The domes of the Pantheon in Rome (118-126), Hagia Sophia (532-537) and Santa Maria del Fiore (1296-1436) are well-known historical examples”
    but I do not know if I need such abbreviations or not. What would you recommend me?

    • Tanya Trusler says:

      Jun 05, 2018 at 3:10 pm

      Hi Iluis,

      It’s really up to you whether you want to include dates or not. It could depend on the context (an architectural magazine, for example, might include dates even for modern buildings), but generally speaking, you’re correct that we’d usually use them for historical buildings.

      I’d consider the buildings in your example historical, and I think it sounds natural to include the dates. I’d suggest including the word “built” in the first example, but I don’t think you’d need to say AD for each one if the context was clear. You could also choose to include AD only for the first one if the context wasn’t clear. Note that en dashes, not hyphens, are preferred when writing dates.

      E.g., “The domes of the Pantheon in Rome (built AD 118–126), Hagia Sophia (532–537) and Santa Maria del Fiore (1296–1436) are well-known historical examples.”

  5. Len says:

    Apr 12, 2018 at 8:29 am

    In UK writing should it be in Italics or roman?

    • Tanya Trusler says:

      Apr 13, 2018 at 1:04 pm

      Hi Len,

      I’m not that familiar with UK style choices, but I do have a copy of The New Oxford Style Manual on my desk and have looked it up for you. They advise writing BC, AD, BCE, and CE in small caps with no periods/points. BC, BCE, and CE follow the date and AD precedes it, as advised above. As for italics, they say, “Small capitals are used for specifying eras. In an italic context they may be set in italics; otherwise, small capitals are generally set in roman type.”

  6. Komal says:

    Mar 07, 2018 at 8:27 am

    I have a problem, I don’t know how many years AD, BC and BCE stands for? If I would say this happened in 209 BC, so how many years it means from now?

    • Tanya Trusler says:

      Mar 07, 2018 at 6:23 pm

      Hi Komal,

      I found this information on the site (

      Calculating Years Across B.C. and A.D.
      “If you have a math problem that requires you to calculate years across B.C. and A.D., it’s crucial to adjust for the fact that there was no year 0. For example, if you need to work out how many years are between January 1, 200 B.C. to January 1, A.D. 700 you add the BC and AD numbers. The calculation is 700 + 200, which equals 900 years. However, you still have to adjust for the absence of year 0. You do this by removing 1 from your answer, so 900 minus 1 is 899.”

      According to these rules, 206 + 2018 = 2224 – 1 = 2223.

      • Tanya Trusler says:

        Nov 20, 2018 at 6:24 pm

        I just noticed I used the wrong start date in my calculations. It should be: 209 + 2018 = 2227 – 1 = 2226.

  7. Hrushikesh says:

    Feb 21, 2018 at 4:22 pm

    While writing a history text do I have to use AD for all the dates in entire document ?

    • Tanya Trusler says:

      Feb 21, 2018 at 7:08 pm

      That depends on the style guide you’re following. If you’re writing for a university, they’ll have a style manual or house style sheet that writers should follow, such as APA format or MLA format. Publishers often follow the Chicago Manual of Style. If you’re writing on your own, you can make your own rules somewhat (as long as they’re logical and, especially, consistent). In general, unless you’re going back and forth between AD and BC/BCE, I’d say you’d only need to say AD once or twice and the rest would be clear from the context.

  8. Lennart says:

    Feb 16, 2018 at 4:01 am

    Great explanation, thanks! I have a question though: If you need to say “He was born in the 900s AD”, how would you write that correctly? It doesn’t feels right to write “He was born in the AD 900s”.

    • Tanya Trusler says:

      Feb 20, 2018 at 2:34 pm

      Hi Lennart,

      That is an excellent question. Unfortunately, CMOS doesn’t provide an example of this. My guess is that we would say “AD 900s” (and Google has many references to it used this way), but I would suggest dropping the “AD” and just say “He was born in the 900s.” Hopefully it would be clear from the context (where you could include a specific date with AD). Another option is to style it “in the tenth century AD” but, even then, CMOS recommends dropping the “AD.” Hope that helps!

  9. Liwell says:

    Jan 15, 2018 at 7:39 am

    Well Elaborate,thank you

  10. Egbaji Austin says:

    Jan 13, 2018 at 9:34 am

    Very clear now, thanks..But how do I get your app? I’m in Nigeria.

    • Tanya Trusler says:

      Jan 15, 2018 at 11:45 am

      Hi Egbaji, you can use this link to subscribe to our site anywhere in the world:

      Our site is mobile-friendly, but we also have an app coming out in March 2018. Please let me know if you have any other questions.

  11. Tanya says:

    Jan 04, 2018 at 1:05 am

    Best explanation, thus far. Thank you.

    • Tanya Trusler says:

      Jan 04, 2018 at 6:49 pm

      Thanks for your comment, Tanya! Nice name too. ;)

  12. priyanshu says:

    Dec 04, 2017 at 12:43 pm

    understood at once….! thnks human

    • Tanya Trusler says:

      Dec 04, 2017 at 4:05 pm

      You’re welcome! No bots here! :)

  13. Johnson ayariga says:

    Oct 17, 2017 at 1:15 pm

    All questions had answered

  14. Barbara Hayes says:

    Oct 12, 2017 at 11:35 am

    So many questions answered – Thank You!

    • Tanya Trusler says:

      Oct 12, 2017 at 12:24 pm

      My pleasure, Barbara.

  15. Grace says:

    Oct 10, 2017 at 10:48 pm

    Clear, concise and helpful information, thank you!

    • Tanya Trusler says:

      Oct 11, 2017 at 12:10 pm

      You’re welcome, Grace! Thanks for commenting.

  16. Satish jain says:

    Oct 04, 2017 at 2:22 pm

    At last understood this! Thanks for explaining.

    • Tanya Trusler says:

      Oct 04, 2017 at 8:17 pm

      You’re welcome, Satish!

  17. Farid says:

    Sep 26, 2017 at 4:08 pm

    I have seen mostly used in Religion historical book… anyway even I didn’t know about it. But now I know!

  18. Ravi Kumar says:

    Sep 22, 2017 at 1:02 pm

    Thank you so much for your great explain, the way of giving example is amazing :)

    • Tanya Trusler says:

      Sep 22, 2017 at 2:02 pm

      Happy to hear it! Thanks, Ravi.

  19. Amudha says:

    Sep 07, 2017 at 5:17 am

    Good clarity

    • Tanya Trusler says:

      Sep 11, 2017 at 7:49 pm

      Great! Thanks for commenting, Amudha.

  20. Prabha says:

    Jun 29, 2017 at 1:27 am

    Really it’s worth full information thank you

  21. Shuchita says:

    Jun 07, 2017 at 10:43 am

    Thanks a lot…It helped…:-)

    • Tanya Trusler says:

      Jun 07, 2017 at 12:34 pm

      I’m happy to hear that!

Sorry, comments for this entry are closed.