I know per annum is from Latin, but what are the real-world differences between these two phrases? Dictionary.com appears to suggest that they are synonyms (see definition below), but I wonder if one used in certain contexts and the other in other contexts?

per annum:

by the year; yearly

3 Answers 3


From the Oxford Corpus of English:


For 30 years, it had gone remorselessly ahead, at about 80% per annum.

An Elan bond, where the bondholder can exercise the right to be repaid in 18 months, currently yields 19 per cent per annum.

With this fresh impetus, the total edible oil processing capacity, including vanaspati, is expected to cross 20 million tonne per annum.


We can currently get about 5% per year from investing in long-dated gilts, so we might aim to get 6% per year from the property.

Penetration of digital has hit 20 % in a year, with incremental revenue per subscriber at $22 per year and growing, he said.

This still leaves teachers $3,000 per year short of accountants, $17,000 short of computer systems analysts, and $25,000 short of engineers.

These example sentences are representative of the most common uses of these two phrases and, as one can see, there is no real difference between per annum and per year in usage.

As kiamlaluno says, per annum is traditionally used more in financial contexts than per year, but these sentences show that per year is also perfectly acceptable.


Per annum is used in financial contexts to mean for each year.


Annum is the Latin word for year. Its meaning in English has not really diverged at all, so it is basically just a snooty (or jargonistic) way to say year. Fewer people know the word, so it is probably a good word to use if you are trying to bury the truth of something under a blanket of obscure verbiage.

The cynic in me begs to point out that financial institutions and lawyers like to use it...

  • 3
    per is also Latin. Some (not me) would look for per annum or a year but try to avoid a mixture of the two languages.
    – Henry
    Jun 29, 2011 at 19:08
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    @Henry - I can see that. In fact, the engineer in me admires that kind of drive for consistency. However, the real goal should just be to communicate well with your audience.
    – T.E.D.
    Jun 30, 2011 at 12:05
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    Hmmm. Reading over my answer and my comment, I appear to have a disturbing number of people "in me". Perhaps I (we?) should see someone about that...
    – T.E.D.
    Jun 30, 2011 at 12:10

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