Writing Numbers in Essays

Convention determines when to use a numeral and when to spell out a number.  Numerals are commonly used in scientific and technical writing and in journalism, but they are used less often in academic or literary writing.

The following guidelines are base on the MLA Handbook for Writers of Research Papers.  APA style, however requires that all numbers below ten be spelled out if they do not represent specific measurements and that the numbers ten and above be expressed in numerals.


Spell the numbers out as words if:
-- you can to so in one or two words; as a rule of thumb, these are numbers one hundred and under;
-- beginning a sentence with a number;


Conventional Uses of Numerals
-- Addresses.  e.g.  111 Fifth Avenue
-- Dates.  e.g. January 15, 1929; 1914 - 1919

-- Exact times.  e.g.  9:16; 10 a.m.; 10:00 a.m. (but spell out times of day when they are used with o'clock:  ten o'clock)
-- Exact sums of money:  e.g.  $25.11; $6,738.00
-- Literary divisions:  e.g.  Act 5; lines 17 - 28; page 42
-- Percentages and decimals:  e.g.  80%; 3.14
Note:  You may spell out a percentage (eighty percent) if you use percentages infrequently in your paper, provied the percentage can be expressed in two or three words.  Always use a numeral (not a spelled-out number) with a % symbol.

-- Measurements with symbols or abbreviations.  e.g.  32°, 15cc

-- Ratios and statistics.  e.g.  20 to 1; a mean of 40

-- Scores.  e.g.  a lead of 6 to 0

-- Identification numbers.  e.g.  Route 66; Track 8; Channel 12

When using numbers, follow the general rules.  However, it's important to be consistent.  If some of your numbers are written as numerals because they're decimals or over 100, then the related numbers should also be written in that manner.