An apparatus for clock calibration on a remote device includes a first oscillator, a second oscillator, and a clock calibration module. The first oscillator generates a first clock signal during an active communication mode to facilitate communications between the remote and host devices. The first oscillator is inactive during a sniff mode. The second oscillator generates a second clock signal during both the active communication and sniff modes. The clock calibration module generates an estimated count for the first clock signal approximately at a transition from the sniff mode to the active communication mode. The estimated count is based on a clock ratio of a baseline count of the first clock signal relative to a baseline count of the second clock signal. The clock calibration module also calculates a difference between the estimated count and an actual count from the host device to determine whether to update the clock ratio.