a rule of thumb

Meaning

1. 1nouncountable

   A practical guideline based on experience that works well in most cases, though it is not exact or scientific.

   Grammar: Countable and usually with a: that is a good rule of thumb; follow some rules of thumb.

   Patterns

   • a rule of thumb for something
   • as a rule of thumb

   As a rule of thumb, allow about an hour for every ten miles of hilly road.

   A good rule of thumb is to save a fifth of your income.

   Cooks follow a simple rule of thumb: salt the water until it tastes like the sea.

Word forms

Common combinations

as a rule of thumb

As a rule of thumb, new tires should be checked monthly.

a handy rule of thumb

Here is a handy rule of thumb for tipping.

a good rule of thumb

A good rule of thumb is to read the question twice.

follow a rule of thumb

Most editors follow a rule of thumb about page length.

general rule of thumb

The general rule of thumb is to arrive early.

Synonyms and how they differ

guideline

Guideline can be official advice from an organization, while a rule of thumb comes from habit and experience.

rough guide

Rough guide openly admits imprecision, and is a little more casual than rule of thumb.

general principle

General principle sounds more formal and more theoretical than a practical rule of thumb.

heuristic

Heuristic is the technical term in science and computing for a quick method that usually works.

Opposites

Word family

rule noun

an instruction about what is allowed or how to do something

thumb noun

the short, thick digit on the hand

rule verb

to control or govern

rule-bound adjective

strictly following rules

Commonly confused: a rule of thumb or rule of law? a rule of thumb or rule of three?

Practice

Make it your own

Write a sentence using “a rule of thumb”, then check it and compare it with the examples above.

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