Sample Size Calculator

Sample Size Calculator helps you determine the required sample size for a given margin of error. Use this free browser-based calculator from XTRAW Tools to compare inputs, estimate results, and plan your next step.

How to Use the Sample Size Calculator

1. Enter the required calculator inputs shown in the form.
2. Review the dataset, sample, confidence level, contingency table, loan amount, rate, or payment assumptions.
3. Run the calculator, then adjust one input at a time to compare scenarios or check your estimate.

What This Calculator Helps With

Determine the required sample size for a given margin of error. It is designed for students, teachers, researchers, analysts, healthcare reference users, survey planners, marketers, and anyone working with statistics who want a fast, browser-based estimate before relying on a spreadsheet, textbook, analytics platform, research software, lender, professional source, or specialist.

• Confidence Level: 95
• Desired Margin of Error: 5
• Population Std Dev (σ): 15
• Population Size (0 = infinite): 0

Common Uses

People use this calculator when they need a quick way to summarize data, compare statistical assumptions, review survey estimates, or check a statistics formula.

• Math Solving: Solve statistics, survey, research, classroom, data analysis, or probability questions from entered values.
• Measurement: Measure variation, percentiles, standard error, confidence intervals, risk, proportions, or dataset summaries.
• Project Planning: Plan research, surveys, experiments, reports, analysis, dashboards, or study workflows using transparent formulas.

Formula or Method

n = (Z × σ / E)²; finite correction: n / (1 + (n−1)/N)

Example

Example inputs: Confidence Level: 95; Desired Margin of Error: 5; Population Std Dev (σ): 15; Population Size (0 = infinite): 0

Example result: Using the default inputs, required sample size is about 35.

Related Tools

• Standard Error Calculator
• Z Score Calculator
• Descriptive Statistics Calculator
• Percentile Calculator
• Odds Ratio Calculator
• Relative Risk Calculator

Sample Size Calculator FAQ

Is the Sample Size Calculator free?

Yes. This calculator is free to use on XTRAW Tools.

Do I need to create an account?

No. XTRAW tools are designed for browser-based use without requiring an account.

Are the results exact?

Results may be estimates depending on the inputs, formula, rounding, statistical method, interpolation method, or purpose of the calculator. Always verify important results before relying on them.

Disclaimer: This calculator is provided for general informational, educational, and convenience purposes only. It is not legal, financial, medical, health, research, statistical consulting, academic, regulatory, safety, or professional advice. Always verify important results with a qualified professional, instructor, statistician, researcher, clinician, authoritative source, or appropriate specialist before making decisions.