Biweekly and bimonthly describe recurring schedules, but both words can be ambiguous. Biweekly can mean every two weeks or twice a week, while bimonthly can mean every two months or twice a month. Major dictionaries recognize both meanings for both words.
In everyday American English, biweekly is often understood as every two weeks, especially when discussing paychecks or recurring meetings. Still, because the word has two dictionary meanings, clear writing should not assume that every reader will interpret it the same way.
When precision matters, phrases such as every two weeks, twice a week, every two months, or twice a month are usually better.
Quick Answer
Biweekly can mean every two weeks or twice a week. Bimonthly can mean every two months or twice a month. Because both terms have two accepted meanings, they can create confusion. For schedules, payments, meetings, or deadlines, use the exact phrase—such as every two weeks or twice a month—when the timing must be clear.
Biweekly vs Bimonthly at a Glance
| Word | Meaning 1 | Meaning 2 | Clearer Alternative |
|---|---|---|---|
| Biweekly | Every two weeks | Twice a week | “every two weeks” or “twice a week” |
| Bimonthly | Every two months | Twice a month | “every two months” or “twice a month” |
The important point is that the prefix bi- does not automatically tell you which frequency is intended. Merriam-Webster explains that bi- can carry either the idea of “every two” or “two times,” which creates the ambiguity.
What Does Biweekly Mean?
Biweekly is an adjective or adverb used for something that happens on a repeating weekly schedule.
It has two accepted meanings:
- Every two weeks
- Twice a week
Cambridge lists both senses, and Merriam-Webster also recognizes the ambiguity.
For example:
We have a biweekly team meeting.
That sentence could mean the team meets once every two weeks.
However, according to the dictionary definition, it could also theoretically mean the team meets twice each week.
Because context may not settle the question, clearer wording would be:
We have a team meeting every two weeks.
or:
We have team meetings twice a week.
What Does Bimonthly Mean?
Bimonthly works in much the same way, except that it refers to months rather than weeks.
It can mean:
- Every two months
- Twice a month
Cambridge gives both meanings, as does Merriam-Webster.
For example:
The newsletter is published bimonthly.
Without more context, a reader may wonder whether the newsletter appears six times per year or about twice each month.
If it is published every two months, write:
The newsletter is published every two months.
If it comes out twice each month, write:
The newsletter is published twice a month.
Those versions remove the ambiguity immediately.
The Main Difference Between Biweekly and Bimonthly
The basic distinction is the time unit.
Biweekly relates to weeks.
Bimonthly relates to months.
The confusing part is that neither word tells you with complete certainty whether the event happens once every two units or twice within one unit. Merriam-Webster specifically describes both terms as inherently ambiguous for this reason.
Compare:
We meet biweekly.
Possible meanings:
- every two weeks
- twice a week
We meet bimonthly.
Possible meanings:
- every two months
- twice a month
That is why these words should be used carefully when exact timing matters.
Does Biweekly Usually Mean Every Two Weeks?
In many common American contexts, biweekly is frequently used to mean every two weeks. Merriam-Webster’s main dictionary entry leads with the “every two weeks” sense while still acknowledging that the word can also mean twice a week.
For example:
Employees receive a biweekly paycheck.
This will often be understood as a paycheck issued once every two weeks.
Still, if you are writing payroll instructions, a contract, schedule, or policy, it is safer to say:
Employees are paid every two weeks.
That wording leaves no room for competing interpretations.
Does Bimonthly Mean Twice a Month?
It can, but bimonthly can also mean every two months.
That makes a sentence such as this risky:
We hold bimonthly meetings.
A reader cannot know from the word alone whether there are approximately six meetings a year or 24 meetings a year.
Cambridge illustrates the “every two months” sense with a publication that produces six issues annually, but its definition also recognizes “twice a month.”
For precision, replace bimonthly with the exact schedule.
Can Biweekly and Bimonthly Mean the Same Schedule?
Surprisingly, yes, approximately.
If biweekly means every two weeks, an event happens about 26 times in a 52-week year.
If bimonthly means twice a month, it happens 24 times in a 12-month year.
Those schedules are close, but they are not identical.
This difference matters especially for payroll and billing. An every-two-weeks schedule does not produce exactly the same number of occurrences per year as a twice-a-month schedule.
So these phrases should not be treated as interchangeable:
Every two weeks ≠ twice a month
Biweekly Pay vs Semimonthly Pay
This distinction is especially important with pay schedules.
Biweekly Pay
When biweekly pay means every two weeks, employees normally receive a paycheck after each two-week period.
A 52-week year divided by two gives:
26 pay periods
Semimonthly Pay
Semimonthly specifically means twice a month, according to Merriam-Webster.
That produces:
24 pay periods per year
For example, a semimonthly employer might pay workers on the 15th and final day of every month.
Therefore:
Biweekly pay = commonly 26 paychecks per year
Semimonthly pay = 24 paychecks per year
The exact dates can vary by employer, but the frequency difference is important.
Biweekly vs Twice a Week
These expressions can technically describe the same frequency because biweekly has an accepted “twice a week” meaning. Cambridge and Merriam-Webster both recognize that sense.
However, writing twice a week is clearer.
Instead of:
We train biweekly.
write:
We train twice a week.
No reader has to stop and interpret the prefix.
Another available word is semiweekly, which Merriam-Webster defines as occurring twice a week.
Even so, twice a week will usually be clearer to a general audience.
Bimonthly vs Semimonthly
This pair is useful when discussing schedules.
Bimonthly can mean either:
- every two months
- twice a month
Semimonthly has the clearer established meaning twice a month.
So:
We issue reports semimonthly.
means the reports come out twice each month.
By contrast:
We issue reports bimonthly.
could be interpreted in two ways.
If complete clarity matters, “twice a month” remains the simplest choice.
Every Two Weeks vs Twice a Month
These schedules may sound almost identical, but they are not.
Every Two Weeks
An event repeats after each 14-day interval.
Over 52 weeks:
52 ÷ 2 = 26 occurrences
Twice a Month
An event happens two times during each calendar month.
Over 12 months:
12 × 2 = 24 occurrences
This difference explains why biweekly payroll and semimonthly payroll should not be treated as the same thing.
Some months on an every-two-weeks schedule can contain three paydays, while a twice-a-month schedule normally has two scheduled paydays each month.
Every Two Months vs Twice a Month
These phrases are much more different.
Every two months means roughly:
January → March → May → July → September → November
That gives about six occurrences per year.
Twice a month means two occurrences each month:
12 × 2 = 24 occurrences per year
Because bimonthly can theoretically express either schedule, relying on that word alone can create a major misunderstanding.
Why Are Biweekly and Bimonthly Ambiguous?
The problem comes from the prefix bi-.
Merriam-Webster explains that bi- can express two different numerical relationships:
- occurring every two
- occurring two times
That allows biweekly to develop both “every two weeks” and “twice a week,” while bimonthly can mean “every two months” or “twice a month.”
This is not merely a recent mistake or a misuse that dictionaries can easily eliminate. Merriam-Webster notes that the ambiguity has existed for a long time and recommends using context when these words could be misunderstood.
How to Avoid Confusion
For casual conversation, biweekly or bimonthly may be fine when everyone already knows the schedule.
For anything important, use exact wording.
Instead of “biweekly,” write:
- every two weeks
- twice a week
Instead of “bimonthly,” write:
- every two months
- twice a month
This is especially useful for:
- pay schedules
- rent or billing
- work meetings
- medication schedules
- publication dates
- contracts
- appointments
- deadlines
The goal is not to avoid correct words. It is to prevent a correct word from being interpreted in the wrong correct way.
Common Mistakes With Biweekly and Bimonthly
Mistake 1: Believing Biweekly Has Only One Meaning
It does not.
Both every two weeks and twice a week are recognized dictionary meanings.
Mistake 2: Assuming Bimonthly Always Means Every Two Months
That is one valid meaning, but twice a month is also established.
Mistake 3: Treating Biweekly and Semimonthly Pay as Identical
They are not identical when biweekly means every two weeks.
Biweekly: about 26 pay periods yearly.
Semimonthly: 24 pay periods yearly.
Mistake 4: Assuming “Bi-” Always Means Every Two
The prefix can also carry the sense twice in these words, which is exactly why the ambiguity exists.
Mistake 5: Using an Ambiguous Word in an Important Schedule
A sentence such as:
Payments are due bimonthly.
may be grammatically correct but practically unclear.
Better:
Payments are due every two months.
Easy Way to Remember the Difference
Start with the final part of each word:
biWEEKly → weeks
biMONTHly → months
That tells you the basic unit.
Then remember that bi- is the confusing part because it may mean either “two times” or “every two.”
So the safest rule is:
Biweekly = something involving a two-week/twice-weekly pattern.
Bimonthly = something involving a two-month/twice-monthly pattern.
When the exact frequency matters, spell it out.
Example Sentences With Biweekly
Every Two Weeks
Our project team meets every two weeks on Friday.
This is clearer than simply saying “biweekly.”
Employees receive biweekly paychecks.
In a payroll context, this commonly refers to an every-two-weeks schedule.
Twice a Week
The class meets twice a week on Monday and Thursday.
Although biweekly can technically express this frequency, twice a week is much clearer.
Example Sentences With Bimonthly
Every Two Months
The committee publishes a report every two months.
This clearly expresses one accepted meaning of bimonthly.
Twice a Month
We hold two training sessions each month.
This clearly expresses the other accepted meaning without forcing the reader to interpret bimonthly.
Frequently Asked Questions
What is the difference between biweekly and bimonthly?
Biweekly refers to a weekly schedule and can mean every two weeks or twice a week. Bimonthly refers to a monthly schedule and can mean every two months or twice a month.
Does biweekly mean every two weeks?
Yes, every two weeks is a standard meaning of biweekly. However, dictionaries also recognize twice a week, so context may be needed.
Does bimonthly mean every two months?
Yes, but that is not its only accepted meaning. Bimonthly can also mean twice a month.
Is biweekly the same as twice a month?
Not when biweekly means every two weeks. Every two weeks produces about 26 occurrences per year, while twice a month produces 24.
What does semimonthly mean?
Semimonthly means twice a month. Because its meaning is more specific, it can be useful when distinguishing a twice-monthly schedule from an every-two-months schedule.
What does semiweekly mean?
Semiweekly means twice a week. Merriam-Webster recommends it as one possible way to avoid the “twice a week” ambiguity of biweekly.
Should I avoid using biweekly and bimonthly?
You do not need to avoid them completely. However, when exact timing affects money, deadlines, meetings, or obligations, every two weeks, twice a week, every two months, or twice a month is clearer.
Conclusion
The difference between biweekly vs bimonthly begins with the unit of time: biweekly relates to weeks, while bimonthly relates to months. The complication is that both words have two accepted meanings. Biweekly can mean every two weeks or twice a week, and bimonthly can mean every two months or twice a month.
