underestimate

Everyday

1. To underestimate means to guess that an amount, size or time is smaller than it really is: «I underestimated how long the walk would take.» tree →
2. To underestimate a person means to think they are less clever, strong or able than they really are. tree →
3. An underestimate (noun) is a guess that is too low. tree →

In the lessons

In maths lessons on estimating and rounding, an underestimate is an estimate lower than the true answer; rounding down often gives one. In stories and sport, a strong team underestimates a small team and loses — a classic lesson. Phrases: «never underestimate», «underestimate someone», «a slight underestimate», «underestimate the danger».

Examples

• I underestimated how many sweets were in the jar: I said 50 and there were 72. tree →
• Never underestimate a small dog! tree →
• The champions underestimated our team and lost 2–1. tree →
• Rounding 48 and 37 down to 40 and 30 gives an underestimate of their sum. tree →
• People often underestimate how cold the sea is in spring. tree →
• Don't underestimate the danger of swimming in a river. tree →
• 200 is an underestimate; the real number is 230. tree →

Note

Verb stress: un-der-ES-ti-mate (last syllable «-mate»); noun: un-der-ES-ti-mut. Opposite: overestimate. Maths: an underestimate is less than the exact answer; rounding every number down gives an underestimate of a sum. Not the same as «underrate», which is only about people's or things' quality, though they overlap.