In keyboard writing, typing skills are considered an important prerequisite of proficient text production. We describe the design, implementation, and application of a standardized copy-typing task in order to measure and assess individual typing fluency. A test-retest analysis indicates the instrument’s reliability. While the task has been developed across eleven different languages and the related keyboard layouts, we here refer to a corpus of Dutch copy tasks (N = 1682). Analyses show that copying speed non-linearly varies with age. Bayesian analyses reveal differences in the typing performance and the underlying distributions of inter-key intervals between the different task components (e.g., lexical vs. non-lexical materials; high-frequent vs. lowfrequent bigrams). Based on these findings it is strongly recommended to include copy-task measures in the analysis of keystroke logging data in writing studies. This supports a better comparability and interpretability of keystroke data from more complex or communicatively-embedded writing tasks across individuals. Further potential applications of the copy task for writing research are explained and discussed.