Formula and method
This calculator uses the values you enter and applies the calculation immediately in your browser. The main output formulas are:
- Margin of error:
p>1 ? NaN : z*Math.sqrt(p*(1-p)/n)*100
Some formulas are undefined for certain input combinations, such as division by zero, equal x-values in a slope calculation, or logarithms of non-positive numbers. In those cases the live tool reports that the result is undefined instead of displaying Infinity or NaN.
Examples
- Example: with Z-score = 1.96, Proportion = 0.5, Sample size = 1000, this calculator returns Margin of error = 3.1 %.
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Frequently asked questions
Is Margin Of Error Calculator free to use?
Yes. Margin Of Error Calculator is completely free, has no usage limit, and does not require an account, email, or API key.
Does Margin Of Error Calculator store or upload my data?
No. Margin Of Error Calculator calculates everything locally in your browser. Nothing you type is sent to a server or stored by SpecWhale.
How accurate is Margin Of Error Calculator?
Margin Of Error Calculator uses a standard formula (see the Method section above for the exact expression). For high-stakes financial, medical, or legal decisions, confirm the result with a professional or an authoritative source before relying on it.
Can I embed Margin Of Error Calculator on my own website?
Yes. Use the "Embed this tool" snippet on this page to add a free, working copy of Margin Of Error Calculator to your own blog post or page.
SEO and sharing notes
This page has a single clean canonical URL, descriptive metadata, breadcrumb structured data, and internal links to related tools. Supported calculators and converters can also copy a prefilled share link without changing the canonical index URL.