User blog comment:123BC/Oliver's kill count/@comment-25224899-20171108023551/@comment-1854917-20171110123942

Agreeing with TheDoctor230 - we can pretty surely count on-screen kills, comparing some cases with confirmed numbers throughout the series, such as 26 in the second half of Season 1 (although this is, of course, excluding the flashbacks which should be accounted separately).