7 Rules of Capitalization

Updated September 2018

Capitalization can be tricky, and the rules of capitalization can vary from language to language.

Knowing when to capitalize letters is important in academic and business writing. So, read the rules of capitalization below. Then do the practice activity!

Rules of Capitalization

Here are some good rules of capitalization to follow:
  1. Capitalize the first word in a sentence.
  2. Capitalize I.
  3. Capitalize names of people, such as JenniferRobert Smith, and the Smith family. This includes capitalizing titles that go with names or instead of names, such as Mr. and Mrs. HernandezDr. Wellington (but not the doctor), Mom (but not my mom), Professor (but not my professor), and Captain (but not their captain).
  4. Capitalize proper nouns, such as the Pacific Ocean, the Mississippi River, the Grand Canyon, the Empire State Building, the Statue of Liberty, O'Hare Airport, Union Station, and Harvard University.
  5. Capitalize the names of streets, cities, counties, states and countries. Example: I live at 500 Spruce Avenue, Columbus, Ohio, in the United States. Another example: Chicago is in Cook County in Illinois.
  6. Capitalize months of the year and days of the week. Example: Today is Sunday, February 12.
  7. Capitalize holidays, such as New Year's Day, Presidents' Day, Independence Day, Memorial Day, Labor Day and Thanksgiving.


So now, let's practice! Look at the sentences below and correct the errors in capitalization. Have fun! Scroll down for the answers.
  1. yesterday was my 40th birthday.
  2. are mr. and mrs. stephens planning to visit their family in texas for thanksgiving?
  3. how old is your dad?
  4. i used to go fishing on that river when i was a boy.
  5. The colorado river is 1,450 miles long.
  6. she grew up in new york.
  7. i've never been to thailand.
  8. have you ever seen the grand canyon?
  9. what did professor harrison say about our final exam?
  10. how long have mom and dad been trying to redecorate the basement?
  11. he is planning to study History at the university of Illinois.


  1. Yesterday was my 40th birthday.
  2. Are Mr. and Mrs. Stephens planning to visit their family in Texas for Thanksgiving?
  3. How old is your dad?
  4. I used to go fishing on that river when I was a boy.
  5. The Colorado River is 1,450 miles long.
  6. She grew up in New York.
  7. I've never been to Thailand.
  8. Have you ever seen the Grand Canyon?
  9. What did Professor Harrison say about our final exam?
  10. How long have Mom and Dad been trying to redecorate the basement?
  11. He is planning to study history at the University of Illinois.

I hope this post has been helpful for you. What do you find most difficult about capitalization? Do you have any tips to help you remember the rules of capitalization? Please share your comments below!

Matthew Huseby, M.A.
My Language Success LLC

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