This paper relates 2-level lambda-calculus and staged lambda-calculus (restricted to 2 stages) to obtain monovariant binding-time analysis for lambda-calculus that produces the output in the form of staging annotations. The relationship between the two lambda-calculi provides us with a precise and easy instruction on how to implement binding-time analysis to be incorporated in the staged lambda-calculus. It forms a basis for introducing binding-time analysis to full-fledged staged languages such as MetaOCaml.