This paper introduces a design algorithm for compliant constant-force mechanisms based on a single straight beam with tailored clamping conditions. Unlike conventional systems, the proposed mechanism achieves a nearly constant output force over a defined displacement range using purely elastic deformation, eliminating the need for traditional joints, actuators, or complex assemblies. Central to the work is a parameterized design algorithm that, given a target force and displacement range, systematically determines feasible beam dimensions, material properties, and the number of beams under geometric, mechanical, and manufacturing constraints. The algorithm integrates dimensionless modeling based on Euler-Bernoulli beam theory, enabling rapid and scalable synthesis of application-specific designs. A representative example demonstrates the algorithm’s capability to efficiently generate a valid mechanism configuration for practical use.