How frequently? Biweekly vs. Semi-weekly

If someone told you paychecks came out biweekly, would you give them a confused look and say, “Twice a week? Why so often?” And if someone said a class met semiweekly on Wednesdays, would you ask them if that was “the first and third or the second and fourth Wednesdays of the month?”

Yes to both? Then read on.

Bi- means “two,” so something that is biweekly occurs every two weeks or every other week. For example, We receive our paychecks biweeekly or about twice a month.

Semi- means “half,” so something that is semi-weekly occurs every half-week or twice a week. To wit, The class meets semi-weekly on Tuesday and Thursday evenings.

Though you now know the difference between the two words, your readers still might not. To prevent confusion, instead write “every other week” for biweekly and “every two weeks” for semiweekly.


My name is Rob Bignell. I’m an affordable, professional editor who runs Inventing Reality Editing Service, which meets the manuscript needs of writers both new and published. I also offer a variety of self-publishing services. During the past decade, I’ve helped more than 300 novelists and nonfiction authors obtain their publishing dreams at reasonable prices. I’m also the author of the 7 Minutes a Day… writing guidebooks, four nonfiction hiking guidebook series, and the literary novel Windmill. Several of my short stories in the literary and science fiction genres also have been published.