CI half-width

Calculate CI half-width instantly with the exact formula and a worked example. Free online calculator — no signup.

CI half-width

p (proportion)
n
z (1.96=95%)
CI half-width
0.098
±z·√(p(1−p)/n)Calculate CI half-width instantly with the exact formula and a worked example. Free online calculator — no signup.
p
0,5
n
100
Lower
0,402
Upper
0,598

More about: CI half-width

What it calculates

The “CI half-width” calculator computes CI half-width from 3 parameters: p (proportion), n, z (1.96=95%).

A core calculation for studying, engineering tasks, and checking solutions.

Example calculation

With parameters p (proportion) = 0.5, n = 100, z (1.96=95%) = 1.96 the result is 0.098 (±z·√(p(1−p)/n)).

How to use

  1. Enter the parameter values — every field above is adjustable with a slider.
  2. The result and related metrics are calculated automatically as you type.
  3. Use the additional metrics shown (if any) where needed.
  4. Copy the result or bookmark the page.

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