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Synonyms

rule of thumb

American  

noun

  1. a general or approximate principle, procedure, or rule based on experience or practice, as opposed to a specific, scientific calculation or estimate.

  2. a rough, practical method of procedure.

rule of thumb British  

noun

    1. a rough and practical approach, based on experience, rather than a scientific or precise one based on theory

    2. ( as modifier )

      a rule-of-thumb decision
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
rule of thumb Cultural  

  1. A practical principle that comes from the wisdom of experience and is usually but not always valid: “When playing baseball, a good rule of thumb is to put your best hitter fourth in the batting order.”

rule of thumb Idioms  

  1. A rough and useful principle or method, based on experience rather than precisely accurate measures. For example, His work with the youth group is largely by rule of thumb. This expression alludes to making rough estimates of measurements by using one's thumb. [Second half of 1600s]

Etymology

Origin of rule of thumb

First recorded in 1685–95

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

“My usual rule of thumb is, move the decimal point one place to the left,” Matheson said.

From Los Angeles Times

A rule of thumb: If I haven’t touched an item since I moved into my current apartment, then it’s not coming with me to the next one.

From MarketWatch

It also incorporates more of people’s financial circumstances than common rules of thumb for equity allocation, such as the classic 60/40 division of stocks and bonds or subtracting your age from 100.

From The Wall Street Journal

One rule of thumb Everstine has is that "if the price seems too good to be true, that should be a red flag".

From BBC

The rule of thumb is well-known: Families are typically told to set aside three to six months’ worth of essential expenses to cover worst-case scenarios and other surprises.

From MarketWatch

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.