What does underestimate mean?
To underestimate is to form a judgment that is too low about someone or something’s size, value, difficulty, importance, strength, or likelihood. The phrase can describe a deliberate mistake as well as an innocent failure to recognize how significant a person or situation is. People may underestimate a competitor, the difficulty of a project, the importance of a detail, or another person’s ability. In the noun form, an underestimate is the resulting judgment: for example, a safety assessment can be described as a serious underestimate of the danger. The word is especially useful when discussing missed opportunities, inadequate preparation, and decisions made on incomplete information. It is related to undervalue and underrate, but its application is broader, covering quantities, risks, abilities, and probabilities rather than only personal worth. Its opposite is overestimate.
To judge the amount, value, difficulty, importance, ability, or likelihood of something as smaller or less significant than it actually is.
"The organizers underestimated the number of people expected to attend."
Common in standard British and American English; often used with risks, abilities, difficulties, quantities, and possibilities.
An estimate that is lower than the actual amount, value, difficulty, importance, ability, or likelihood involved.
"The budget was based on a severe underestimate of the repairs required."
Usually countable and commonly used with an adjective such as serious, major, or slight.
The plural form is underestimates, as in ‘the report contained several underestimates.’
"The planning document was full of underestimates about costs and staffing."
Underestimating is often less about a weak guess than about failing to give a possibility its full due.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does underestimate come from?
The English word combines the prefix under-, meaning below or less than, with estimate, from Latin aestimare, meaning to appraise or value. Both elements were established in English before the compound became common. The transparent structure of under- plus estimate reflects the basic meaning: to value or judge something below its actual worth.
Related word forms
How underestimate is actually used
Underestimate is common in both formal and informal English. It is often used when someone fails to recognize a risk, difficulty, ability, or possibility, and can imply that the person making the error has limited experience or information.
Easily confused with underestimate
To underestimate is to judge a value, ability, or quantity too low, whereas to understate is to represent something as less important or smaller than it really is, often deliberately.
Underestimate focuses on making a low estimate, while undervalue focuses specifically on judging someone or something as having less worth or importance than it deserves.