What does computable mean?
"Computable" is an adjective meaning capable of being calculated, determined, or worked out through a systematic process of computation. In everyday contexts it describes quantities or outcomes that can be derived arithmetically — a sum, a cost, a probability. In mathematics and computer science it takes on a stricter, foundational meaning: a function or problem is computable if some algorithm, in principle a Turing machine, can produce its answer in finitely many steps. This technical sense became central to twentieth-century logic, when Alan Turing and Alonzo Church formalized what machines can and cannot do, proving that certain well-defined problems are provably not computable. The word derives from Latin roots via "compute," sharing ancestry with "count." It belongs primarily to formal, academic registers, and its antonyms include "incalculable" and "noncomputable." Understanding "computable" offers insight into the very limits of mechanical reasoning.
adjectiveAble to be calculated, determined, or worked out by computation; in mathematics and computer science, capable of being computed by an algorithm or Turing machine.
- Capable of being calculated or worked out numerically.
- (Mathematics/computer science) Capable of being computed by an algorithm or Turing machine.
"The total cost of the project was computable from the figures already on file."
"The interest owed was precisely computable once the principal and rate were known."
"Kurt Gödel and Alan Turing showed that some mathematical questions are not computable by any algorithm."
In the 1930s, Alan Turing proved that some perfectly well-defined problems are simply not computable by any machine — and his proof laid the foundation for every computer ever built.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of computable
"Computable" comes from the verb "compute," which entered English in the 17th century from Latin "computare" — "com-" (together) plus "putare" (to reckon or count). The same Latin root gives English "count," "account," and "dispute." The adjective took on special significance in the 1930s, when Alan Turing and Alonzo Church independently formalized the notion of algorithmic computability, making the word a term of art in mathematical logic.
Related word forms
How computable is actually used
Formal register, used chiefly in mathematics, logic, and computer science, though it also appears in general contexts where something is said to be calculable. In technical use it carries precise meaning relating to decidability and algorithmic computation; in everyday use it overlaps with "calculable."
Easily confused with computable
"Countable" means able to be enumerated (listed one by one), while "computable" means able to be calculated or determined by a computational process — a set can be countable without its members being computable.