back-of-the-envelope
Proposed by a contributor, not yet supported by evidence.
Meaning · English
A rough and approximate calculation or estimate
Literally: a calculation written on the back of an envelope
Where it’s used:
Used
Widespread English
Examples
The investor made a back-of-the-envelope calculation to determine the project's potential return
AI-drafted example auto-approved by rule (illustrative, not a corpus attestation)
Sources & notes
Listed in Wiktionary’s “English idioms” category (retrieved 2026-07-29); definition pending editorial review. Definition drafted by AI (@cf/meta/llama-3.3-70b-instruct-fp8-fast) and auto-approved by rule on 2026-07-30; pending editor spot-check.
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Common questions
What does “back-of-the-envelope” mean?
A rough and approximate calculation or estimate Literally: a calculation written on the back of an envelope
Is “back-of-the-envelope” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.
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