What does antilog mean?
An antilog, short for antilogarithm, is the inverse of a logarithm: given a logarithmic value, it returns the original number that produced it. If the logarithm of 1000 to base 10 is 3, then the antilog of 3 is 1000 — formally, raising the base to that power. The term belongs to the vocabulary of mathematics, engineering, chemistry, and statistics, where logarithmic scales such as pH, decibels, and Richter magnitudes must be converted back into ordinary quantities. Before electronic calculators, printed tables of logarithms and antilogarithms were essential tools for multiplication and division, and the word retains a slightly old-fashioned, technical flavour today. In modern practice, computing an antilog usually means applying an exponential function, such as 10 to the power x or e to the power x. The abbreviated form 'antilog' is informal but widely understood among students and professionals who work with logarithmic data.
nounAn antilog is the number whose logarithm a given value represents; in other words, the result obtained by raising the base of a logarithm to a specified power. It is the inverse operation of taking a logarithm.
- The inverse of a logarithm: the number obtained when a base is raised to a given exponent, written as base^x where x is the logarithm.
"To recover the original measurement from its log-transformed value, simply take the antilog."
"Since the logarithm of 1000 to base 10 is 3, the antilog of 3 is 1000."
"The chemist took the antilog of the pH reading to find the hydrogen ion concentration."
Standard plural, used when referring to multiple antilog values or table entries.
"The appendix lists both the logarithms and the antilogs for quick reference."
Before calculators, every slide rule and log table user lived by one rule: logs to multiply, antilogs to get back home.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of antilog
The word antilog is a clipped form of antilogarithm, coined on the model of 'logarithm' itself, a term introduced by the Scottish mathematician John Napier in the early seventeenth century from Greek 'logos' ('ratio, reckoning') and 'arithmos' ('number'). The prefix 'anti-' reflects the inverse relationship between the two operations. As logarithm tables became widespread in the seventeenth century, the shortened forms 'log' and 'antilog' emerged as convenient colloquial abbreviations in mathematical and scientific writing.
How antilog is actually used
Antilog is an informal abbreviation of 'antilogarithm', common in mathematics education, engineering, and scientific contexts. It appears most often in discussions of logarithm tables and pre-calculator computation methods, and is typically used attributively or as a verb-like instruction ('take the antilog').
Easily confused with antilog
An algorithm is a step-by-step procedure for solving a problem, while an antilog is the inverse of a logarithm — despite their superficially similar spellings.
An antilogarithm is simply the full, formal name for the same concept that 'antilog' abbreviates.