Proposed is a practical model for predicting creep and shrinkage of concrete from the composition of concrete mix, strength, age at loading, conditions of environment, size and shape, etc. The main features are: double power law for basic creep, square-root hyperbolic law for shrinkage, diffusion-type size dependence of humidity effects, additive drying creep term related to shrinkage, and activation energy treatment of thermal effects. Optimization techniques are used to fit numerous test data available in the literature. The work is a continuation of previous investigations and consists of several parts. This first part deals with shrinkage.