Frequency expressions (once a week, twice a month)

What are frequency expressions?

Frequency expressions tell us how often something happens. They answer the question 'How often?' and are useful for talking about habits, routines, and regular events. Unlike simple frequency adverbs (always, usually, never), frequency expressions use numbers and time periods combined together. They help you be more specific and precise about time patterns in daily life.

How to form frequency expressions

The basic structure is: NUMBER + TIME PERIOD. Common number words include once (1×), twice (2×), three times, four times, etc. Time periods are day, week, month, year, and hour. You can also use 'a' or 'an' before the time period, or use 'per' instead. For example: once a day, twice a week, three times a month, four times per year. These expressions usually come at the end of a sentence or after the main verb.

Position in sentences

Frequency expressions have flexible word order. They typically appear at the end of a sentence: 'I go to the gym twice a week.' However, you can also place them at the beginning for emphasis: 'Twice a week, I go to the gym.' In questions, they usually go at the end: 'How often do you visit your family?' 'Once a month.' Never place them between the subject and auxiliary verb like simple frequency adverbs.

Frequency Expressions at a Glance

Number Word	Connector	Time Period	Full Expression	Example Sentence	Note
once	a / per	day	once a day	I take this pill once a day.	"once" = 1 time; informal preferred
twice	a / per	day	twice a day	She checks her email twice a day.	"twice" = 2 times; informal preferred
three times	a / per	day	three times a day	He eats three times a day.	3+ uses "[number] times"
once	a / per	week	once a week	We have a meeting once a week.	"a" is more common in speech
twice	a / per	week	twice a week	I go to the gym twice a week.	"per" is more formal/written
three times	a / per	week	three times a week	She volunteers three times a week.	Pattern: [number] times a/per [period]
once	a / per	month	once a month	I visit my grandparents once a month.	Also: "monthly" (one-word adverb)
twice	a / per	month	twice a month	The report is due twice a month.	Also: "twice monthly" (adverb form)
four times	a / per	month	four times a month	We meet four times a month.	≈ once a week
once	a / per	year	once a year	We take a holiday once a year.	Also: "annually" (formal)
twice	a / per	year	twice a year	Dentists recommend check-ups twice a year.	Also: "biannually" (formal)
once	every	other day / two days	once every other day	I water the plants once every other day.	"every other" = every 2nd; use "every" for irregular gaps

Formula

✔ Positive

Subject + verb + object/complement + frequency expression

I visit my parents twice a month.

? Question

How often + do/does + subject + verb + object?

How often do you go to the gym?

Examples

She drinks coffee three times a day.

Daily routine · Specific frequency

We have team meetings once a week on Monday mornings.

Work context · Regular schedule

My dentist recommends brushing your teeth twice a day.

Health advice · Health & hygiene

I see my grandparents four times a year during holidays.

Family visits · Seasonal pattern

The bus arrives every twenty minutes, so about three times per hour.

Public transport · Calculated frequency

How often do you exercise? Twice a week, usually on Wednesday and Saturday.

Question response · Fitness routine

When to use it

Daily routines and habits

Describe how often you do everyday activities like exercise, eat, sleep, or work. These expressions help create clear pictures of your lifestyle.

"I eat lunch at 12 o'clock three times a week at my favourite café."

Health and medical advice

Medical professionals use frequency expressions to give clear instructions about medication, exercise, or check-ups.

"Take this medicine twice a day with food."

Work schedules and meetings

In workplace communication, frequency expressions clarify how often meetings happen, deadlines occur, or tasks need completing.

"We have project updates once a week every Friday afternoon."

Social activities and events

Talk about how often you see friends, attend classes, or participate in activities and clubs.

"I see my best friend twice a month, usually on weekends."

Signal words

once twice three times four times a day a week a month a year per hour per day per week

Common Mistakes

Wrong

I go to the gym twice per a week.

✓

Correct

I go to the gym twice a week.

Use 'a' or 'per', not both. Choose: 'twice a week' or 'twice per week'.

Wrong

Three times a week I go shopping always.

✓

Correct

I go shopping three times a week.

Avoid mixing frequency expressions with simple frequency adverbs like 'always'. Use one or the other.

Wrong

She practices piano one times a day.

✓

Correct

She practices piano once a day.

Use 'once' (not 'one time') for single occurrences. 'One time' is less formal and typically not used this way.

Wrong

How often visits he his family once a month?

✓

Correct

How often does he visit his family? Once a month.

In questions with 'how often', use normal question word order with the auxiliary verb (does/do).

KEY TAKEAWAYS

What to Remember

Frequency expressions combine a number word (once, twice, three times) with a time period to show how often something happens.
Use the structure NUMBER + TIME PERIOD, like "twice a week" or "three times a month," for precise frequency statements.
Place frequency expressions at the end of sentences or after the main verb, not at the beginning like simple adverbs.
Remember that "once" means one time, "twice" means two times, and "three times" onwards follows the pattern for all other numbers.
Frequency expressions are more specific than simple adverbs like "usually" or "often," so use them when you need exact time patterns.

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Ever and never — usage and comparison

Adverbs of frequency — common mistakes