Proportion Uncertainty

The amount of uncertainty in a proportion is not intuitive.  Use this tool to help understand how much uncertainty exists in a calculated proportion.  In other words, how sure are you that the proportion is that number and not higher or lower?  The amount of uncertainty is affected by both sample size and the value of the proportion, i.e. its position within the distribution.  For example, values towards the extremes (closer to 0% or 100%) have less uncertainty than those in the middle close to 50%.