Good news for fans of Batman and Superman as in addition to the earlier news of the 10 Justice League movies on the way, also mentioned in the official WB press release is that standalone movies for the Caped Crusader and the Man of Steel are in development.
And, in a massive expansion of the Studio’s DC Entertainment-branded content, Warner Bros. Pictures and New Line Cinema will release a slate of at least 10 movies—as well as stand-alone Batman and Superman films—from 2016 through 2020 that expands this prized universe of characters
2013 saw the launch of the new DC movie universe with Man of Steel led by Henry Cavill, which raked in about $668 million worldwide.
Shortly after the Man of Steel's opening there was talk of a sequel; however, instead of a straight up standalone Superman movie, Batman was announced as part of the cast with Ben Affleck. Following that saw the addition of Wonder Woman Gal Gadot, with the full title becoming known, which obviously introduces the Justice League with "Batman v Superman: Dawn of Justice."
WB has yet to announce the release dates for the Batman and Superman standalone films or even the year they will come out, but we can guess both films will come after the 2017 Justice League movie as it's been said that Zack Snyder is filming both Batman vs. Superman and the Justice League movie back-to-back.
Taking a look at the current DC schedule, it's probably likely that the Batman and Superman films will be released prior to the second Justice League movie, which hits some time in 2019.
“Batman v Superman: Dawn of Justice,” directed by Zack Snyder (2016)
“Suicide Squad,” directed by David Ayer (2016)
“Wonder Woman,” starring Gal Gadot (2017)
“Justice League Part One,” directed by Zack Snyder, with Ben Affleck, Henry Cavill and Amy Adams reprising their roles (2017)
"The Flash,” starring Ezra Miller (2018)
“Aquaman,” starring Jason Momoa (2018)
“Justice League Part Two,” directed by Zack Snyder (2019)
“Cyborg,” starring Ray Fisher (2020)
“Green Lantern” (2020)