before you know it
Also found in: Acronyms.
before you know it
Quickly or suddenly. I'm not far from your house, so I'll be there before you know it. Before you know it, you'll be graduating, so start thinking about your future now.
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.
before you know it
almost immediately. I'll be there before you know it. If you keep spending money like that, you'll be broke before you know it.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
before you know it
see under before you can say Jack Robinson.
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.