extrapolate

American  

[ik-strap-uh-leyt] / ɪkˈstræp əˌleɪt /

verb (used with object)

extrapolated, extrapolating

1. to infer (an unknown) from something that is known; conjecture.

2. Statistics. to estimate (the value of a variable) outside the tabulated or observed range.

3. Mathematics. to estimate (a function that is known over a range of values of its independent variable) to values outside the known range.

---

verb (used without object)

extrapolated, extrapolating

1. to perform extrapolation.

extrapolate British  

/ ɪkˈstræpəˌleɪt /

verb

1. maths to estimate (a value of a function or measurement) beyond the values already known, by the extension of a curve Compare interpolate

2. to infer (something not known) by using but not strictly deducing from the known facts

---

extrapolate Scientific  

/ ĭk-străp′ə-lāt′ /

1. To estimate the value of a quantity that falls outside the range in which its values are known.

---

Other Word Forms

• extrapolation noun
• extrapolative adjective
• extrapolator noun
• extrapolatory adjective
• overextrapolation noun

Etymology

Origin of extrapolate

First recorded in 1825–35; extra- + (inter)polate

Explanation

When you extrapolate, you use specific details to make a general conclusion. For example, if you travel to Canada and encounter only friendly, kind natives, you might extrapolate that all Canadians are friendly. The verb extrapolate can mean "to predict future outcomes based on known facts." For example, looking at your current grade report for math and how you are doing in class now, you could extrapolate that you'll likely earn a solid B for the year. Another meaning of extrapolate is "estimate the value of." You could extrapolate how much your antique watch is worth by finding how much similar watches sold for at recent auctions.

Example Sentences

Mr Justice Nicklin started to ask what the best single piece of evidence for each article was, and Sherborne was forced to say: "We are asking your lordship to extrapolate."

From BBC • Mar. 31, 2026

Legendary investor Jeremy Grantham suggests that markets extrapolate current conditions into the future, rather than predicting significant changes.

From Barron's • Jan. 29, 2026

“Even when we extrapolate the best-case scenario for chip production from our suppliers, it’s still not enough,” he said.

From MarketWatch • Nov. 8, 2025

You can’t just take an analysis of the past, no matter how careful it is, and assume you can extrapolate it into the future.

From The Wall Street Journal • Oct. 31, 2025

Then, after all your manipulations are complete, you take the limit: you extrapolate and figure out where the expression is headed.

From "Zero: The Biography of a Dangerous Idea" by Charles Seife

Related Words

• deduce
• hypothesize