Knowing what counts as common knowledge helps you decide when to cite a source and when a citation isn’t necessary. Some facts are universally known, while others require proper attribution to avoid plagiarism. This guide explains how to recognise common knowledge with clear rules and examples.
When You Don’t Need a Citation
Common knowledge refers to information most readers already know or can easily verify in many reliable sources. These facts don’t belong to one specific author and are widely accepted across textbooks, encyclopedias, and general education. Because of this, they don’t require a citation. Here are some examples and why they qualify:
Water freezes at 0°C.
The Earth orbits the sun.
World War II ended in 1945.
Shakespeare wrote Hamlet.
When It Looks Common but Actually Needs a Citation
Sometimes a fact sounds familiar enough to feel like common knowledge—but that doesn’t mean you can use it without a citation. Many statements that appear obvious are actually based on specific research, statistics, or expert interpretations. This section shows how to spot those borderline cases that do require proper referencing.
72% of teens use social media daily
Daily meditation reduces anxiety by 34%
Breakfast improves academic performance in children
Exercise boosts memory and learning ability
Common Knowledge Test
Deciding whether something counts as common knowledge can feel confusing, but a simple rule helps: if a fact appears in many reliable sources and no single author claims ownership of it, it’s usually common knowledge. But if the information traces back to one researcher, one study, or one specific publication, then you must cite it.
When in doubt, use the quick test below to guide your decision. If all the statements in the checklist below are true, the information is likely common knowledge. If not, you should cite the source.
Is It Common Knowledge?
Understanding what counts as common knowledge—and what requires a citation—helps you write confidently, avoid plagiarism, and maintain academic integrity. The simple rules and examples above give you a practical foundation for making smart citation decisions in any assignment.
If you still have questions about when to cite, how to reference correctly, or what counts as plagiarism, the FAQ section below offers quick, clear answers to the most common concerns students face.
