A server chassis includes an uninterruptible power supply, and a server including a controller. The uninterruptible power supply is configured to provide a reserve power when a primary power is lost, and to send a power loss signal when the primary power is lost. The controller is configured to receive a desired server uptime, to receive an indication that a power limit for the server is fixed or decreasing over the desired server, to receive the power loss signal from the uninterruptible power supply, to send a power capacity query to the uninterruptible power supply, to receive a reserve power capacity of the uninterruptible power supply in response to the power capacity query, to calculate the power limit for the server based on the reserve power capacity of the uninterruptible power supply and on the desired server uptime, and to enforce the power limit on the server.