err on the side of caution

American

[er on thuh sahyd uhv kaw-shuhn, ur] / ˈɛr ɒn ðə ˈsaɪd əv ˈkɔ ʃən, ˈɜr /

idiom

to reduce risk by planning or acting more carefully than might seem absolutely necessary.

Budget for all your known expenses, but err on the side of caution by also allowing funds for unforeseen circumstances.
Sorry, but I removed your image from the thread—it’s probably not offensive, but I always err on the side of caution with such things.

Etymology

Origin of err on the side of caution

First recorded in 1780–90

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.

People don’t know how long they will live, so they err on the side of caution.

From MarketWatch • Apr. 16, 2026

Meta says Instagram's new alerts - stemming from its analysis of user search patterns - may occasionally alert parents when there is no cause for concern and will "err on the side of caution".

From BBC • Feb. 26, 2026

Leaders’ first instinct was to err on the side of caution.

From The Wall Street Journal • Nov. 11, 2025

Doctors often give antibiotics to err on the side of caution, but that’s not recommended unless there’s evidence of a bacterial infection; overuse of the drugs can exacerbate the development of antibiotic resistance.

From Science Magazine • May 1, 2024

Many people living outside the evacuation zone in Fukushima decided to err on the side of caution, too.

From "Meltdown" by Deirdre Langeland

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