What Is Fermi Estimation: How to Estimate Anything
Fermi estimation is the skill of making reasonable approximations from first principles, even with little data.
What has been corrected on this page?
Every accepted correction to this page is recorded with the exact change, so readers can see how the page improved over time.
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Corrected an internal inconsistency: the article's own internet-weight calculation (mass of electrons in transit) yields about 0.45 grams, but the text then claimed this 'yields a similar order of magnitude' to a commonly cited 50-gram figure - actually about two orders of magnitude apart. Corrected to note the two figures differ substantially, illustrating that Fermi estimates can diverge depending on which assumptions (such as which layer of network data is counted) are used. The U.S. GDP (~$25 trillion), CTIA text-message data (~2 billion/day), and the geometric-mean explanation of why independent estimation errors partially cancel were verified accurate and appropriately hedged already.
What the page claimedThe article's own math gave 0.45 grams for the internet's electron mass but claimed this matched a commonly cited 50-gram figure as 'a similar order of magnitude,' though the two differ by roughly 100x.
What was correctedCorrected the claim to accurately describe the size of the discrepancy between the calculation and the commonly cited figure.
Why: This was an internal arithmetic inconsistency: the article's own numbers contradicted its stated conclusion. Correction aligns the text with the article's own math rather than adding new sources.
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The author of Guesstimation is Lawrence Weinstein (co-author John A. Adam) of Old Dominion University, not 'Peter Weinstein' of the College of New Jersey.
BeforePhysicist and educator Peter Weinstein of the College of New Jersey
AfterPhysicist and educator Lawrence Weinstein of Old Dominion University
Why: Verified live: the correction was already applied to the article body exactly as suggested. FAQ/excerpt/meta_description/seo_keywords contained no leftover reference to the fabrication, and no separate bibliography section exists on this page. No further action needed.
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