Magnetometers are an integral part of attitude determination system for the low-Earth orbiting small satellites as they are lightweight, inexpensive and reliable. Yet using magnetometers for attitude determination is not straightforward because of the sensor errors. These errors limit the overall achievable attitude determination accuracy. Thus far different methods to cope with magnetometer errors and calibrate the magnetometers have been proposed. A new research field is the specific errors for magnetometers onboard the small satellites and their time-variation characteristics. In accordance, algorithms which consider also the time-varying error terms are proposed. This paper reviews the recent calibration algorithms for small satellite magnetometers. The survey mainly covers batch and recursive estimation algorithms which are capable of estimating the time-varying magnetometer error terms. It presents the foundation of each algorithm and covers issues about the algorithm design, application and performance. In the end possible directions in this research field are briefly discussed.