They would approximate a thumb\u2019s width to about an inch. It was very useful to carpenters, masons, tailors, and brewers, for example.<\/p>\n\n\n\n
Many rules of thumb have been widely used in business and everyday life contexts, such as lifestyle, personal budgeting, healthy eating, and productivity.<\/p>\n\n\n\n
In this article, you will learn the meaning and origin of \u2018rule of thumb\u2019 along with practical examples of the phrase.<\/p>\n\n\n\n
Let’s jump in.<\/p>\n\n\n\n
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Key Takeaways<\/strong><\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n Rule of Thumb is an idiom that means to perform an action based on your experiences instead of precise, calculated decisions. <\/p>\n\n\n\n We can say that it is a practical guideline to do something quickly when a 100% accuracy is not needed. Rule of thumb actions do work well enough to get you through most of the real life situations.<\/p>\n\n\n\n The reason we make ‘rule of thumb’ decisions is that they are tried-and-tested methods that have worked for other people in everyday practice. It’s just common sense to follow the same methods.<\/p>\n\n\n\n The origin of the phrase ‘rule of thumb’ takes us back to the time in history when certain professions used different parts of the human body as measuring aids.<\/p>\n\n\n\n Many trades, such as carpenters, masons, tailors, and brewers, used the width of a thumb as a reference for their measurements. The wish of a thumb was equivalent to an inch in cloth trading.\u00a0<\/p>\n\n\n\n The earliest appearance of the idiom in print was in 1685. It is said that the Scottish preacher James Durham wrote in one of his sermons, <\/p>\n\n\n\n “Many profest Christians are like foolish builders, who build by guess, and by rule of thumb (as we use to speak), and not by Square and Rule.<\/em>“<\/p>\n\n\n\n It became more common in writing by the late seventeenth and early eighteenth centuries. <\/p>\n\n\n\n We see the first usage of the phrase as it is used in a modern context in a collection of Scottish proverbs written by James Kelly in 1721, which reads,<\/p>\n\n\n\n “No Rule so good as Rule of Thumb, if it hit<\/em>“<\/p>\n\n\n\n A modern folk story also claims that the ‘rule of thumb’ came from an old English law allowing a man to beat his wife with a stick no thicker than his thumb.<\/p>\n\n\n\n However, that is a myth that has been debunked because there are no sources that say whether any such law existed.<\/p>\n\n\n\n It was, however, associated with domestic abuse in the 1900s for some time. The United States Commission on Civil Rights in 1982 created a report, “Under the Rule of Thumb” on domestic abuse.<\/p>\n\n\n We use ‘rule of thumb’ to describe circumstances when a rough guide or general guidance is sufficient to move forward. It is an informal alternative to a strict set of rules you must follow.<\/p>\n\n\n\n These rules simply help us go about our lives without over-analyzing our daily life choices. <\/p>\n\n\n\n Here are some examples of \u2018rules of thumb\u2019 in everyday life:<\/p>\n\n\n\n Business decisions are full of uncertainty, so it is a common practice, and a pretty good one, to just follow the rules that have previously worked for many experts in your industry. <\/p>\n\n\n\n Forbes even published an article<\/a> on why rules of thumb from experts in your field work well in business decisions.<\/p>\n\n\n\n You don’t want to overwhelm your mental capacity by making sure every single everyday action is based on data. At a workplace, we’re expected to make hundreds of mciro-decisions everyday, and doing so will only lead us towards decision fatigue.<\/p>\n\n\n\n A very well-known rule of thumb that many businesses take into account is the Pareto principle<\/a>, better known as the 80\/20 rule.<\/p>\n\n\n\n It suggests that around 80% of your revenue comes from 20% of your customers. Of course, it is only an estimation, the 80% revenue in your specific business may be coming from 23% customers, or someone else’ s may be 18%.<\/p>\n\n\n\n The 5% percent rule in financial reviews, which says that up to 5% fluctuations in income are background noise rather than meaningful chances in your revenue, is another example of a general rule of thumb in businesses.<\/p>\n\n\n\n In everyday life too, many ideas that apply to lifestyle, personal budgeting, healthy eating, productivity, etc, are so popular that they are considered rules of thumb.<\/p>\n\n\n\n The 50\/30\/20 rule in personal finance, where you allocate 50% of your income to needs, 30% to your wants, and 20% to savings, is commonly implemented.<\/p>\n\n\n\n There are many, many other things that we are taught to just do out of habit that have become rules of thumb.<\/p>\n\n\n\n For example:<\/p>\n\n\n\n And all of us choose to follow the rules of thumb that fit best with our goals. You can find many more examples through the Undetectable AI’s AI Chat<\/a>.<\/p>\n\n\n “Rule of thumb” is a noun phrase in which ‘rule’ and ‘thumb’ are nouns and ‘of’ is a modifier. It is most often paired with an article, and in most cases, you’ll use it with \u201ca.\u201d<\/p>\n\n\n\n Sometimes, the article “the” may also be used if a specific guideline is being talked about.<\/p>\n\n\n\n For example:<\/p>\n\n\n\n As a noun phrase, it is used as the subject of a sentence with a singular verb, e.g. “A rule of thumb makes our decisions easy.” Note that the singular form of the verb with an -s (makes) is used.<\/p>\n\n\n\n The standard spelling for the phrase is not hyphenated, so the rule-of-thumb will not be grammatically very accurate.<\/p>\n\n\n\n The most frequent usage of the phrase happens in conversational English and in news and media writing. It is far less common in formal business documents or scientific writing.<\/p>\n\n\n When you’re learning how to use ‘rule of thumb’ in your sentences, always make sure to run your text through Undetectable AI’s Grammar Checker<\/a> to ensure that you’ve followed all these rules.<\/p>\n\n\n\n If you missed any, the tool will correct them for you, and you’ll also be able to learn from your mistakes in real time.<\/p>\n\n\n\n It is very common for English learners to have a hard time understanding the correct usage of idioms, and the ‘rule of thumb’ is no different.<\/p>\n\n\n\n Some people end up misusing it in situations where they also simultaneously mention an exact measurement.<\/p>\n\n\n\n For example, \u201cThe rule of thumb is to cook the steak for exactly five minutes,\u201d is grammatically incorrect because you can’t use ‘rule of thumb’ and ‘exactly’ in the same breath.<\/p>\n\n\n\n A better way to phrase this sentence would be, “The rule of thumb is to cook the steak for about five minutes.\u201d<\/p>\n\n\n\n You will sometimes incorrectly hear “the thumb rule” being used in the same sense. It is a non-standard version of the idiom, and it’s best that you stick to the grammatically and linguistically accepted form, ‘rule of thumb.’<\/p>\n\n\n\n\n
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\n\n\n\nWhat Is the Rule of Thumb?<\/h2>\n\n\n\n
Rule of Thumb Origin <\/h3>\n\n\n\n
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<\/picture><\/figure><\/div>\n\n\nRule of Thumb in Everyday Life<\/h2>\n\n\n\n
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<\/picture><\/figure><\/div>\n\n\nHow to Use Rule of Thumb in a Sentence<\/h2>\n\n\n\n
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![\"Undetectable](\"https:\/\/undetectable.ai/blog\/wp-content\/uploads\/2025\/07\/Free-Grammar-checker-1024x432.jpg\")
<\/picture><\/figure><\/div>\n\n\nTips and Common Mistakes<\/h2>\n\n\n\n