# Sample Size Calculator wth Proportion Percentage, formulas

# Sample-Size Calculator

An online sample size calculator with and without finite population corrections.

**Sample Size Formula**

n = z^{2} * p * (1 - p) / e^{2}

Where,

z value (e.g. 1.96 for 95% confidence level)

p = proportion (as a decimal),

e = margin of error (%).

**Sample Size (with finite Population Correction)**

n = [z^{2} * p * (1 - p) / e^{2}] / [1 + (z^{2} * p * (1 - p) / e^{2} * N)]

Where,

z value (e.g. 1.96 for 95% confidence level)

p = proportion (decimal),

N = population size,

e = margin of error.

**Detailed Description:**

Population Size - The total number of people whose opinion or behaviour your sample will represent.

Confidence Level (%) - The Probability that your sample accurately reflects the attitudes of your population.The industry standard is 95%.

Margin of Error (%) - The range (measured as a percentage) that your populations response may deviate from your samples.

## z value

Our calculator used the following z-score values.

Confidence Level | z-score |
---|---|

70% | 1.04 |

75% | 1.15 |

80% | 1.28 |

85% | 1.44 |

90% | 1.645 |

91% | 1.7 |

92% | 1.75 |

93% | 1.81 |

94% | 1.88 |

95% | 1.96 |

96% | 2.05 |

97% | 2.17 |

98% | 2.33 |

99% | 2.576 |

99.5% | 2.807 |

99.9% | 3.29 |

99.99% | 3.89 |

##### How the sample size used in Survey?

Sample Size can be used in different areas in the world and some of them are

1/ Market research and development(R&D)

2/ Customer satisfaction surveys(CSR)

3/ Education surveys(ES)

4/ Employee and human resources surveys(HRS)

5/ Healthcare surveys(HCS)

6/ Casual surveys