A term which may be expressed infinitesimally at time

by the differential

.
For a finite time interval the quotient is
The quantities

and

are of the same kind and have the same type of component. Fractional change has dimension
one. Examples are: mass fractional change,

;
amount of substance fractional change,

.
Source:
PAC, 1992, 64, 1569
(Quantities and units for metabolic processes as a function of time (IUPAC Recommendations
1992))
on page 1571
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.