Hint: Use this calculator to determine the number of samples for achievement percentage (for example accuracy or first-time-right percentage) so as to compare with a standard expected or target value.

Confidence Level

The minimum acceptable probability of preventing type I error

90%

95%

99%

99.9%

Power of Test

The minimum acceptable probability of preventing type II error

50%

80%

90%

95%

99%

Assumed Proportion

This is the standard or target or the known proportion. For 50%, just enter 50

Acceptable Difference %

Or Margin of Error. Alternatively, if you know the sample proportion, then it is difference between the assumed and the sample proportion. For 5%, just enter

Sample Size (1-proportion test)

Minimum samples required to check if your proportion matches with the standard or known proportion