Sample Size Calculator
Find the sample size your survey needs.
Uses Cochran's formula with finite-population correction when a population size is provided: n₀ = z²·p·(1−p) / e². Plan for non-response by inflating the target (e.g. ÷ expected response rate).
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About this tool
‘How many respondents do I need?’ is the most common — and most consequential — methodology question. Too few and your tests lack power; too many and you waste months of fieldwork.
This calculator gives you a defensible sample size from your population, confidence level and margin of error, following the standard Cochran/Krejcie–Morgan logic committees recognise.
How to use it
- 1Choose the confidence level — 95% is the research standard.
- 2Set the margin of error (5% is the common choice) and leave response distribution at 50% for the most conservative estimate.
- 3Enter your population size if it's known and finite; leave it blank for large or unknown populations.
- 4Read the recommended sample size and note all four parameters — you'll report them in your methodology chapter.
Frequently asked
Is 100 respondents enough for my study?+
It depends on your population and analysis. Simple descriptive surveys may manage; regression and SEM need power-based numbers — often 200–400 for typical models. Justify with a calculation, not a convention.
What sample size does SEM need?+
CB-SEM (AMOS) usually wants 200+ with reasonably normal data; PLS-SEM (SmartPLS) tolerates less but still requires power-based justification — the '10-times rule' is only a floor.
Go deeper
Research Methodology guidesRAC in PhD: Full Form, Meaning, Roles, Process & FAQs (2026 Guide)
PhD Coursework in India: Syllabus, Credits & How to Clear It
How to Write the Limitations of the Study (Without Undermining It)
How to Write the Research Methodology Chapter (Structure + Worked Example)
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