Table 3. Sample size required for surveys.

Estimated population size	Margin of error
	Confidence level 95%			Confidence level 99%
	5%	2.5%	1%	5%	2.5%	1%
100	80	94	99	87	96	99
500	217	377	475	285	421	485
1,000	278	606	906	399	727	943
10,000	370	1332	4899	622	2098	6239
100,000	383	1513	8762	659	2585	14227
500,000	384	1532	9423	663	2640	16055
1,000,000	384	1534	9512	663	2647	16317

Sample size is larger for a lower margin of error or higher level of confidence. Once the estimated population size is very large (>100,000), the sample size is not changing much.