A minimax approximation algorithm (or L^∞ approximation or uniform approximation) is a method to find an approximation of a mathematical function that minimizes maximum error.

For example, given a function ${\displaystyle f}$ defined on the interval ${\displaystyle [a,b]}$ and a degree bound ${\displaystyle n}$, a minimax polynomial approximation algorithm will find a polynomial ${\displaystyle p}$ of degree at most ${\displaystyle n}$ to minimize

${\displaystyle \max _{a\leq x\leq b}|f(x)-p(x)|.}$