back-of-the-envelope

adjective

: done quickly to provide a rough estimate : not exact

did a back-of-the-envelope calculation

His method is, in effect, a back-of-the-envelope time-and-motion study.

—Ian Stewart

Examples of back-of-the-envelope in a Sentence

Recent Examples on the Web

Doing some quick back-of-the-envelope math on the President’s numbers - 200 ships and 100 million barrels of oil - implies about 500,000 barrels of oil per ship. — Brian Sullivan, CNBC, 11 June 2026

Now borrow Virginia’s price and lay it over Pennsylvania’s pipeline, as a back-of-the-envelope test rather than an official figure. — Dara-Abasi Ita, Forbes.com, 10 June 2026

My back-of-the-envelope reckoning shows that at present, with more partisan changes likely, Republicans across the South from Texas to South Carolina and Florida are projected to capture 83 congressional seats to 22 for Democrats. — Jim Nowlan, Chicago Tribune, 20 May 2026

By my back-of-the-envelope calculation, under this system the overall federal rate on a taxable income of $1 million would come to a rate of about 29%. — Business Columnist, Los Angeles Times, 6 May 2026

The back-of-the-envelope math all pointed to catastrophe. — Arkansas Online, 19 Mar. 2026

Both memoirs prepare the lay gambler for a world of gruelling, bruising defeats and unglamorous back-of-the-envelope calculus. — Dan Piepenbring, New Yorker, 4 Feb. 2026

Even simple back-of-the-envelope and spreadsheet models, using historical hourly data, tell a more consistent story. — Alex Pavlak, Baltimore Sun, 1 Feb. 2026

Caveating that many basic questions remain unanswered, a back-of-the-envelope calculation shows a clear trade-off between immediate monthly affordability and long-term debt accumulation. — Preston Fore, Fortune, 12 Nov. 2025

Word History

First Known Use

1968, in the meaning defined above

Rhymes for back-of-the-envelope

• radioisotope
• antelope
• bronchoscope
• cantaloupe
• cystoscope
• endoscope
• envelope
• epitope
• gyroscope
• horoscope
• isotope
• microscope