If you are having a 2011 Macbook Air, would suggest you to think again before calibrating the battery of your computer.
There are numerous posts about the ways and advantages of recovering battery condition through calibration. They worked nicely on my previous Macbook Airs, but not on the 2011 model.
I did three times on my machine last year, and each time the battery health status dropped even a bit further after calibration.
Three times are more than enough. I stopped doing that since last November. And up to now, the health of my battery remains unchanged.
Probably the battery used on the 2011 Macbook Air is different from before.
Anyway, just a note : Do think before you calibrate the battery of your 2011 Macbook Air.
Update on May-4:
The health of the battery is getting better from 95% to 96% after keeping the machine running as normal discharging and charging usages.