Percent or Per Cent? (Writing Percentages)

At Proofed, we always put 100% into our work. But wait, is that right? Not the level of effort (we’re confident on that one).

The real question is whether we’ve expressed the percentage correctly. There are so many ways of writing the darn things, after all! Herein, then, we’ll look at your options for handling percentages in different types of writing.

Words or Numbers?

When writing percentages, the same rules apply as for writing numbers of any kind. Generally, this means that you should write numbers up to ten as words and anything larger as numerals.

This also affects how you write the ‘percentage’ bit of percentages. For example, when a percentage is represented with a numeral, it should be accompanied by the ‘%’ sign:

Studies show that 48% of people use numbers incorrectly.

But when following a number written out in full, you should use words:

Ten percent of respondents spelled their own names wrong.

This is particularly common in formal writing or when using a percentage at the beginning of a sentence. However, this may depend on whether you’re using a particular style guide (e.g. in technical and scientific writing, numerals and the ‘%’ sign are used in most cases).

Percent or Per Cent?

We know now that percentages are sometimes expressed in words, but we still have another big question: should it be one word or two?

The answer? It doesn’t really matter.

Both ‘percent’ and ‘per cent’ are acceptable. The one-word version is more common these days, especially in America, but both are variations on the Latin per centum, which means ‘by the hundred’.

If your university or employer has a style guide, check whether they prefer using ‘percent’ or ‘per cent’. Most of the time, though, either is fine as long as you’re consistent.

When to Use ‘Percentage’

Finally, we have the word ‘percentage’. This term has the same root as ‘percent’, but it’s used in a different way. The key is that ‘percentage’ is not typically used with a specific number.

In practice, this means that we use ‘percent’ (or the ‘%’ symbol) when we’re discussing a particular percentage. If we’re talking about a general amount, however, we can use ‘percentage’ instead:

Research indicates that 98 percent of bees have knees.

We need to study what percentage of ants have elbows.

This is because ‘percentage’ is only ever a noun, while ‘percent’ typically modifies another word.