This paper presents a fast and accurate algorithm for printing floating-point numbers in both free- and fixed-format modes. In free-format mode, the algorithm generates the shortest, correctly rounded output string that converts to the same number when read back in, accommodating whatever rounding mode the reader uses. In fixed-format mode, the algorithm generates a correctly rounded output string using special # marks to denote insignificant trailing digits. For both modes, the algorithm employs a fast estimator to scale floating-point numbers efficiently. Keywords: floating-point printing, run-time systems 1 Introduction In this paper we present an efficient floating-point printing algorithm, which solves the output problem of converting floating-point numbers from an input base (usually a power of two) to an output base (usually ten).