How to use this calculator
- Select a confidence level.
- Choose an acceptable margin of error.
- Enter the expected proportion or use 50% conservatively.
- Enter the eligible population, or 0 if it is large or unknown.
Estimate the user sample needed to measure a dashboard adoption proportion with a specified confidence level and margin of error. Enter an expected adoption rate and the size of the eligible user population. The calculator first computes the large-population requirement, then applies a finite-population correction when appropriate. The result addresses sampling precision, not nonresponse, tracking gaps, or whether the selected users represent the rollout population.
n₀ = z² × p × (1 − p) ÷ e²
For known population N: n = n₀ ÷ (1 + (n₀ − 1) ÷ N). The final result is rounded up.
The result is the minimum completed, usable sample under simple random sampling assumptions. It does not repair selection bias or incomplete measurement.
Plan additional outreach or collection when some sampled observations may be missing, ineligible, or unusable.
At 95% confidence, a ±3-point margin, 35% expected adoption rate, and 12,000 eligible users, the adjusted requirement is 899 users; the large-population requirement is 972.
For a binary proportion, variability is greatest at 50%, so it produces the most conservative requirement when the true rate is uncertain.
It tells the calculator to use the large or unknown population formula without a finite-population correction.
No. Increase the outreach or eligible collection target to allow for expected nonresponse, exclusions, or unusable observations.
Not directly. This formula estimates one proportion; a two-group comparison needs assumptions about both rates, allocation, significance, and power.
Tighter precision requires more information. Sample size grows approximately with the inverse square of the margin of error.
| Symbol | Meaning |
|---|---|
| z | Confidence z-score |
| p | Expected proportion |
| e | Margin of error |
| N | Finite population, if known |