Numbers, measurements and units

See Notes for Authors p. 22 for detailed guidance.

Brief guidelines as below:

• use numerals

o whenever a number is followed by a unit symbol (for example kg, m)

o for references to illustrations

o for dates, page numbers, percentages and expressions of time

o where several numbers are used in succession, some less and some more than ten, use numerals throughout

o use decimals and never fractions

• use words

o for numbers from one to ten; numerals for larger numbers

o in whole numbers containing several zeros, either substitute a word for part of the number (e.g. 16 million instead of 16 000 000)

o do not begin a sentence with a numeral

• spaces and markers

o use a full point for the decimal marker e.g. 16.6 kg

o numbers with up to four digits or fewer on either side of the decimal marker are set without spaces or commas: 616, 1684, 0.8333

o numbers with more than four digits are divided by a fixed space, not a comma, every three digits from the decimal marker: 25 000, 1 584 000, 0.616 42

• units

o millions: use m and decimals: 1 m, 1.5 m, 20 m

o billions: use bn and decimals: 1 bn, 1.5 bn, 20 bn

o per cent should be spelt out, not %