Sample Size Calculator For 1 Proportion Test

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

Find where to start, and get on the right track

Our learning pathways guide you on the path to success in business excellence.

Explore our learning pathways