To monitor data duplication progress, embodiments of the present disclosure relate to a method and apparatus for determining data duplication progress in real-time. The method comprises initiating a duplication of data from a source system to a destination system. The method further comprises determining first duplication progress for an initial stage of the duplication, original data existing on the source system when the duplication is initiated being duplicated in the initial stage. Furthermore, the method further comprises determining, independently from the initial stage, second duplication progress for a delta stage of the duplication, delta data being duplicated in the delta stage and including at least data generated during the initial stage. The present disclosure develops a fine-grained monitoring mechanism of data duplication progress.