Software performance can be predicted based on different system configurations. In one example, a computing device can receive historical datasets associated with copies of a software application executed by a group of computing environments during a prior timespan. Each historical dataset can indicate respective changes during the prior timespan to at least one performance characteristic of one of the copies of the software application executed by one of the computing environments in the group. Each computing environment in the group can being configured differently than the other computing environments in the group. The computing device can also convert the historical datasets into training data for a machine-learning model, and train the machine-learning model. This can yield a trained machine-learning model configured to generate a forecast of the performance characteristic for the software application over a future timespan.