Methods and systems are provided for a compressor having a variable inlet device and an active casing treatment. In one arrangement, a system for a compressor may include a casing forming a recirculation passage surrounding an inlet passage, an active casing treatment surrounding the inlet passage and configured to selectively control gas flow through the recirculation passage, an impeller, and a variable inlet device positioned in the inlet passage upstream of the impeller and configured to selectively reduce an effective size of the impeller. The variable inlet device and the active casing treatment may be adjusted based on operating conditions in order to increase a flow range of the compressor while providing high compressor efficiency.