Units of Measure - Abbreviations

AMA Manual of Style - Stacy L. Christiansen, Cheryl Iverson 2020

Units of Measure
Abbreviations

Quantitative values may be reported in conventional units or by using the International System of Units (“SI units” [Système International d’Unités]) (see 17.5.10, Laboratory Values, and 17.1, SI Units). JAMA Network journals report most analytes in conventional units.

Use the following abbreviations and symbols with a numerical quantity in accordance with guidelines in 17.0, Units of Measure. See especially 17.5, Conventional Units and SI Units in JAMA Network Journals; 17.5.10, Laboratory Values; and 8.4, Forward Slash [Virgule, Solidus]).

In rare instances, it may be appropriate to use teaspoon, cup, pound, mile, and so on in a scientific article when, for example, describing a survey in which such units may have been used in the original questionnaire. Conventional-unit equivalents may then be included parenthetically or in an explanatory footnote (as in a table or figure).

Note: Do not capitalize abbreviated units of measure (unless the abbreviation itself is always capitalized or contains capital letters).

Abbreviations listed in this section can be used without expansion except where noted otherwise. The abbreviations for measures of time (day, hour, millisecond, minute, month, second, week, and year) should be used only in a virgule construction and in tables and figures.

Unit of measure

Abbreviation

acre

acre

ampere

A

angstrom

Convert to nanometers (1 A = 0.1 nm)

atmosphere, standard

atm

bar

bar

barn

b (expand at first mention)

base pair

bp (expand at first mention)

becquerel

Bq

billion electron volts

GeV (expand at first mention)

Bodansky unit

BU (expand at first mention)

British thermal unit

BTU

calorie

cal

candela

cd (expand at first mention)

Celsius

C (See policy about use of degree symbols in 18.1.5, Measures of Temperature.)

centigram

cg

centimeter

cm

centimeters of water

cm H2O

centimorgan

cM

centipoise

cP

coulomb

C (expand at first mention)

counts per minute

cpm

counts per second

cps

cubic centimeter

cm3 (use milliliter for liquid and gas measure; avoid cc)

cubic foot

cu ft

cubic inch

cu in

cubic meter

m3

cubic micrometer

µm3

cubic millimeter

mm3 (use microliter for liquid and gas measure)

cubic yard

cu yd

curie

Ci

cycles per second

Use hertz

dalton

Da

day

d (use only in virgule construction, tables, and figures)

decibel

dB

decigram

Convert to grams

deciliter

dL

decimeter

Convert to meters

diopter

D (expand at first mention)

disintegrations per minute

dpm (expand at first mention)

disintegrations per second

dps (expand at first mention)

dyne

dyne

electron volt

eV

electrostatic unit

ESU (expand at first mention)

equivalent

Eq

Fahrenheit

F (See policy about use of degree symbols in 18.1.5, Measures of Temperature.)

farad (electric capacitance)

F (expand at first mention)

femtogram

fg

femtoliter

fL

femtomole

fmol

fluid ounce

fl oz

foot

ft (convert to meters; query author)

gas volume

gas volume

gauss

G

gigabyte

GB

grain

grain

gram

g

gravity (acceleration due to)

g (use closed up to preceding number, eg, 200g)

gray

Gy

henry

H (expand at first mention)

hertz

Hz

horsepower

hp

hour

h (use only in virgule construction, tables, and figures)

immunizing unit

ImmU (expand at first mention)

inch

in

international benzoate unit

IBU (expand at first mention)

international

unit IU

joule

J

katal

kat (expand at first mention)

kelvin

K

kilobase

kb (expand at first mention)

kilobyte

kB

kilocalorie

kcal

kilocurie

kCi

kilodalton

kDa

kiloelectron volt

keV

kilogram

kg

kilohertz

kHz

kilojoule

kJ

kilometer

km

kilovolt

kV

kilovolt-ampere

kVA

kilovolt (constant potential)

kV(cp) (expand at first mention)

kilovolt (peak)

kV(p) (expand at first mention)

kilowatt

kW

King-Armstrong unit

King-Armstrong unit

knot

knot

liter

L

lumen

lumen

lux

lux

megabyte

MB

megacurie

MCi

megacycle

Mc

megahertz

MHz

megaunit

megaunit

megawatt

MW

meter

m

metric ton

metric ton

microampere

µA

microcurie

µCi

microfarad

µF (expand at first mention)

microgram

µg

microliter

µL

micrometer

µm

micromicrocurie

Use picocurie

micromicrogram

Use picogram

micromicrometer

Use picometer

micromolar

µM

micromole

µmol

micron

Use micrometer

micronormal

µN

microosmole

µOsm

microvolt

µV

microwatt

µW

mile

mile

miles per hour

mph

milliampere

mA

millicurie

mCi

millicuries destroyed

mCid (expand at first mention)

milliequivalent

mEq

millifarad

mF (expand at first mention)

milligram

mg

milligram-element

mg-el (expand at first mention)

milli—international unit

mIU

milliliter

mL

millimeter

mm

millimeters of mercury

mm Hg

millimeters of water

mm H2O

millimolar

mM

millimole

mmol

million electron volts

MeV

milliosmole

mOsm

millirem

mrem

milliroentgen

mR

millisecond

ms (use only in virgule construction, tables, and figures)

milliunit

mU

millivolt

mV

milliwatt

mW

minute (time)

min (use only in virgule construction, tables, and figures)

molar

M

mole

mol

month

mo (use only in virgule construction, tables, and figures)

morgan

M (expand at first mention)

megaunit

MU (expand at first mention)

mouse unit

MU (expand at first mention)

nanocurie

nCi

nanogram

ng

nanometer

nm

nanomolar

nM

nanomole

nmol

newton

N

normal (solution)

N

ohm

Ώ

osmole

osm

ounce

oz

outflow (weight)

C (expand at first mention)

parts per million

ppm

pascal

Pa

picocurie

pCi

picogram

pg

picometer

pm

picomolar

pM

picomole

pmol

pint

pt

pound

lb (convert to milligrams, kilograms, or grams; query author)

pounds per square inch

psi

prism diopter

PD, Δ (expand at first mention)

quart

qt

rad

rad

radian

radian

rat unit

RU (expand at first mention)

revolutions per minute

rpm

roentgen

R

roentgen equivalents human (or mammal)

rem

roentgen equivalents physical

rep

Saybolt seconds universal

SSU (expand at first mention)

second

s (use only in virgule construction, tables, and figures)

siemens

S

sievert

Sv

sp g

specific gravity (use with a number, eg, sp g 13.6)

square centimeter

cm2

square foot

sq ft

square inch

sq in

square meter

m2

square millimeter

mm2

Svedberg flotation unit

Sf (expand at first mention)

terabyte

TB

tesla

T

torr

Use millimeters of mercury

tuberculin unit

TU

turbidity-reducing unit

TRU (expand at first mention)

unit

U

volt

V

volume

vol

volume per volume

vol/vol

volume percent

vol%

watt

W

week

wk (use only in virgule construction, tables, and figures)

weight

wt

weight per volume

wt/vol

weight per weight

wt/wt

yard

yd

year

y (use only in virgule construction, tables, and figures)