Guide · Citations

APA vs Harvard vs IEEE: which citation style do you need?

Three of the most common university citation styles, what they look like, and which subjects use them — so you can pick the right one with confidence.

By Sadat Ahmed · 17 June 2026

Different fields settled on different citation styles, which is why there's no single "correct" way to reference. The three you'll meet most often at university are APA, Harvard and IEEE. Here's how they differ and how to know which one your assignment wants.

Quick comparison

StyleIn-textCommon in
APAAuthor–date, e.g. (Smith, 2024)Psychology, education, social sciences, nursing
HarvardAuthor–date, e.g. (Smith 2024)Business, humanities; widely used in UK & Australian unis
IEEENumbered, e.g. [1]Engineering, computer science, IT

APA

APA uses an author–date system and is the standard across the social sciences. References are listed alphabetically, and in-text citations pair the author with the year.

Harvard

Harvard is also author–date and looks similar to APA, but it isn't a single fixed standard — institutions publish their own slightly different versions. That's why your university's Harvard guide is the one that counts.

IEEE

IEEE is a numbered style used in technical fields. Each source gets a number in square brackets in the order it first appears, and the reference list is ordered by those numbers rather than alphabetically.

So which do you use?

Your assignment brief or unit outline almost always specifies the style — start there. As a rough rule of thumb: social sciences lean APA, business and humanities often use Harvard, and engineering and computer science use IEEE. When in doubt, ask your tutor; using the wrong style can cost easy marks.

Open the citation generators →

Frequently asked questions

How do I know which style to use?

Check your unit outline or assignment brief first — it almost always names the required style. If not, ask your tutor.

Can I mix citation styles in one document?

No. Pick the one your course requires and use it consistently throughout.

Are these the only citation styles?

No — others like MLA, Chicago and Vancouver exist. APA, Harvard and IEEE are among the most common in universities.

Related

Citation styles have institution-specific variations. Always confirm the exact format with your university's official guide.