Numbers

Rule: Spell out a number when it begins a sentence or when it is below 10, when writing sentences or not referring to measurements/medicine. Otherwise, use the number and ‘st’/ ‘nd’/ ‘rd’/ ‘th’. Don’t use superscript.

Example: Ten new employees started on Monday, and 12 start next week. She got a 3rd class degree. He has type 2 diabetes. It's the 2nd day.

Rule: In numbers of more than three digits, use a comma after every third digit from right to left. Decimal numbers are separated by a point.

Example: $ 3,450.95; 1.5 L

Rule: Spell out fractions, use a hyphen.

Exception: Use fractions in images.

Rule US: Use the % symbol instead of spelling out ‘percent’. There is no blank space between the number and the %-sign. Repeat the % symbol when addressing a span.

Example: 23%, 20%–30%

Rule: Use a dash (–) to indicate a range or span of numbers.

Example: It takes 20–30 days

Rule: There is a blank space between the number and weight and height. Always write kg first and lb in brackets. Write cm first and ft and in brackets.

Example: 58 kg (127.9 lb), 56.5 kg (124.6 lb), 150 cm, 149.9 cm (4 ft 11 in)

Rule: Always round to one digit and do not use spaces.

Example: 38.2°C, 12.5 km

Rule: Do ratios as follows:

• Blood pressure: leave space between units, note capitalization

Rule: Do ratios as follows:

• Heart rate: write number and unit with a slash

Rule: Do ratios as follows:

• Liter: Capitalize

• Note capitalization of Hg

Example: dL; mEq/L; g/dL; mm Hg; IU/mL

Rule: Do ratios as follows:

• Subscription and superscription if it's necessary

Example: CO₂; cm²; pCO₂

Rule: When writing about US currency, use the dollar sign before the amount. Include a decimal and number of cents if more than 0.

Example: $20; $19.99

Rule: There is no blank space between the number and temperatures (Celcius, Fahrenheit). Always round to one digit!

Example: 24.0°C, 100.0°C, 94.5°F