The online poll shows 47.98 for Clinton, compared to 47.24 for Trump.
Each candidate dropped two-tenths of a point in Tuesday's poll, with the percentage of "others" increasing by four-tenths. "Others" in the poll are defined as respondents who decline to pick either Clinton or Trump.
The UPI/CVoter online tracking poll surveys about 200 people each day, leading to a sample size of roughly 1,400 people during any seven-day span.
Because the poll is conducted online and individuals self-select to participate, a margin of error cannot be calculated. The poll has a credibility interval of 3 percentage points. This seven-day span includes data collected from Aug. 15-21, when 1,795 individuals were surveyed. Of them, 1,259 identified themselves as likely voters.