Sample sizes necessary for estimating survival rates of banded birds are derived based on specified levels of precision. The equations are derived for studies involving adults only, or adults and young, and the banding study can be new or ongoing. Precision is based on the desired coefficient of variation (CV) of the survival estimates. The CV for annual survival estimates, the CV for mean annual survival estimates, and the length of the study must be specified to compute sample sizes. A computer program, BAND2, has been written to compute the necessary sample sizes given the desired precision level and the length of the study. A description of the input and output for this program is provided.