In the blink of an eye Informal

Extremely quickly, almost instantaneously.

It’s often used for a sudden change or event, emphasizing how little time passed between one state of affairs and a very different one.

The phrase’s roots are biblical: the Apostle Paul, in 1 Corinthians 15:52, described the resurrection using a Greek phrase meaning “a quick flicking of the eye,” which Jerome’s Latin Vulgate rendered as “in ictu oculi” (“in a stroke of the eye”). English translations preserved this image for centuries with the word “twinkling” rather than “blink”: Robert Manning of Brunne’s 1303 “Handlyng Synne” used “yn twynkelyng of an ye,” John Wycliffe’s 1382 Bible kept “in the twynklyng of an iye,” and the 1611 King James Bible standardized it as “in a moment, in the twinkling of an eye, at the last trump.” The word “blink” itself only entered English around the 1580s (from Middle Dutch “blinken,” to glitter) and did not firmly settle into its modern sense of an involuntary eye closure until the mid-19th century, at which point writers began swapping the newer, more everyday “blink” in for the older, more literary and biblical “twinkling,” producing the now-dominant modern phrasing.

The whole thing happened in the blink of an eye.

Prices changed in the blink of an eye.

She finished the race in the blink of an eye.

A: “How fast did it go by?” B: “In the blink of an eye.”