Different organisations have different takes on this, and perhaps the most important thing is to be consistent.
Many publishers produce style guides to inform their writers of an approach to take; On Point Copywriting has adopted The Economist Style Guide.
The rule is: One to ten should be written as words, and thereafter as numerals.
However, there are a few exceptions to this:
* When describing a measurement, always use numerals e.g. 5%, 7 miles.
* If a decimal is present, use numerals e.g. 1.75.
* Never use numerals at the start of a sentence – always write the number.
Another quirk is that if you are writing a list numbers, with some numbers being below ten and some being higher, use numerals for all e.g. The top three teams’ points totals were 5, 12, and 8.
The next time you’re unsure about whether to write a number or use numerals, remember that rule of thumb, which should help on most occasions:
One to ten should be written as words, and thereafter as numerals.
If you need any more advice, call us on 0117 244 0116.