Non inferiority sample size calculator
Use our non inferiority sample size calculator to calculate accurate size and measurement values instantly.
Calculator
Approximate per-group sample size for a two-arm non-inferiority design (normal approximation).
Formula: n per group approx = 2 x (Zalpha + Zbeta)^2 x p(1-p) / margin^2
What each field means
- Alpha (e.g. 0.025): Example: 0.025
- Power (%): Example: 80
- Event Proportion (0-1): Example: 0.5
- Non-Inferiority Margin (absolute): Example: 0.1
Approximate n Per Group
Your result will appear here.
About Non inferiority sample size calculator
The Non inferiority sample size calculator helps you estimate sample size and statistics values quickly using consistent assumptions and practical calculation rules.
Formula Explanation
n per group approx = 2 x (Zalpha + Zbeta)^2 x p(1-p) / margin^2
Inputs You Need
- Required measurement values relevant to this calculator
- Unit selection: Alpha (e.g. 0.025), Power (%), Event Proportion (0-1), Non-Inferiority Margin (absolute)
- Optional tolerance, safety, or scenario values if applicable
Step-by-Step Usage
- Enter your known values in the calculator fields.
- Select units and options that match your scenario.
- Click Calculate to generate your output.
- Copy, save, or share the result for later reference.
Example
Run the tool with realistic values from your use case and compare the output against expected ranges for sample size and statistics calculations.
Method Sources
- https://www.calculator.net/sample-size-calculator.html
- https://en.wikipedia.org/wiki/Sample_size_determination
Frequently Asked Questions
Is this Non inferiority sample size calculator accurate?
Yes, when correct inputs and units are provided.
Which units does this calculator support?
This tool is optimized for Alpha (e.g. 0.025), Power (%), Event Proportion (0-1), Non-Inferiority Margin (absolute).
Can I use this calculator on mobile?
Yes, the form is optimized for touch inputs and smaller screens.