As a rule (of thumb)

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Senior Member
Mandarin / the Shanghai Dialect

What is the difference between “as a rule of thumb” and “as a rule”? Are they interchangeable in the following examples from the free dictionary?

1. As a rule of thumb, I move my houseplants outside in May.

2. As a rule, things tend to get less busy after supper time.

Rule of thumb:

a general principle developed through experiential rather than scientific means

rule of thumb

As a (general) rule:

Typically; most of the time.

as a rule
  • entangledbank

    Senior Member
    English - South-East England
    Sentence 1 sounds wrong. I would think people usually or typically (as a rule) move their plants in May. There's no rough guide, or approximate way of deciding something (a rule of thumb) involved in it.


    Senior Member
    USA, English
    A rule of thumb is a generally recognized recommendation.

    As a rule of thumb it is suggested that house plants be put outdoors in the summer.

    A rule is something that is recognized as factual.

    As a rule it is mandatory that you bring the houseplants indoors before the first frost.


    Senior Member
    English - England
    I don’t see them as synonymous.

    As a rule of thumb = as a makeshift way of assessing this…
    As a rule = in general / normally


    Senior Member
    USA, English
    Some background on "rule of thumb". This site gives a definition (shown) and some historical background (not shown).

    'Rule of thumb' - the meaning and origin of this phrase
    What's the meaning of the phrase 'Rule of thumb'?

    A rule of thumb is a means of estimation made according to a rough and ready practical rule, not based on science or exact measurement.
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