# factor in

CEFR B2 · Phrasal verb

Source: https://englishreference.com/word/factor-in
Updated: 2026-10-22

## Definition

To include a particular fact or situation when you are planning something or making a decision. You use this when you need to think about all the details before you decide.

For teachers: To include a specific variable or piece of information as a relevant element when performing a calculation or making an assessment. Transitive; the object can be a noun phrase or a 'that' clause.

## Examples

- You must factor in the cost of shipping before buying the car.
- When planning the outdoor wedding, the couple had to factor in the possibility of heavy rain and rent a tent.
- Economists must factor in the volatility of global oil prices when projecting the domestic inflation rate for the upcoming fiscal year.

## Pitfalls

- Not "We factored the extra costs." but "We factored in the extra costs." — The particle 'in' is essential to convey the meaning of inclusion; without it, 'factor' has a different mathematical or causative meaning.

## Usage notes

- Usually followed by a noun representing a cost, time, or risk that affects a final result.
- Teaching tip: Contrast with 'account for'; 'factor in' is specifically about including a variable in a calculation or decision process.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.