Math & Statistics
Margin of Error Calculator
Find the margin of error for a survey proportion.
Your inputs
Change any value to update the result instantly.
Margin of error
4.8999 %
Lower bound
45.1001 %
Upper bound
54.8999 %
Z-score
1.96
Formula and working
E = z·√(p(1−p) ÷ n)
- 1
Collect the inputs
Sample proportion = 0.5; Sample size = 400; Confidence level = 95
- 2
Apply the formula
E = z·√(p(1−p) ÷ n)
- 3
Result
Margin of error = 4.8999 %
Frequently asked questions
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
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