Sample size calculator for estimating a proportion & with a detectable change to a known proportion  Sample size for detetcting a change  
  Known proportion P0
This is the known proportion,
known from other sources than from a sample survey
  by Ruilin Ren, PhD Type I error (α)
This is the type one error for a two-tailed test; the default value is set to 0.05 if not provided
This is the power of the test; the default value is set to 80% if not provided
This is the net sample size needed for detecting the difference between P and P0 if the desired sample size is not specified; otherwise, it gives the power of the test.
  Current estimated proportion P
This cell is for the reference indicator which must be a decimal number.
Specified  size
This cell is for the desired sample size which is in priority.
  Target population size
This cell is for the target population size when it is small.
Estimated Deft
This cell is for design effect Deft which is the square root of Deff. It is necessary for a cluster or multi-stage sampling.
  Sample Size  95% confidence limits of P  
  Individual Lower-limit Upper-limit  
You can specify the desired relative standard error here other than the above given ones
  * Only the light green colored cell (for current P) must be filled. Input for other dark green colored cells are optional.  
  * The sample size calculated/you specified are net sample size without taking non-response into account.  
  * The sample size calculated for detecting a change is based on a two-sided test with α=5% and β=80%.