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Region: General | Usage example: We started with a back-of-the-envelope estimate.

Back of the envelope

Meaning

A quick, rough calculation.

Usage

Used when describing informal planning.

Origin & History

Origin notes can vary by region and source; this page gives the commonly reported explanation and usage context.

Engineers scribbled quick math on envelope backs.

Adopted in engineering in the 20th century.

Related Idioms

Back to the drawing board

Return to planning stage after a failure.

Push the envelope

Challenge limits or experiment beyond norms.

Get back in the saddle

Return to an activity after a setback.

More Idioms

Break the ice

To do or say something to relieve tension or get conversation going in a social situation.

Cut to the chase

Skip ahead to the most important or exciting part of something.

The ball is in your court

It is now your turn to take action or make a decision.

Throw in the towel

To concede defeat or admit a struggle isn't worth continuing.