71.8 watt-hour: 2013 13" MacBook Pro [1] 49.2 watt-hour: 2016 13" MacBook Pro Touch [2] Why are so many people surprised that the battery life went down from ~10 hours down to ~7 hours? When the physical battery size is only ~70% of the previous model, it's no surprise the new MacBook Pro only gets ~7 hours of battery life. [1] https://support.apple.com/kb/sp691?locale=en_US [2] http://www.apple.com/macbook-pro/specs…
Apple claims a 10 hour battery life on the 2016, and 9 hours on the 2013 for both the wireless web and iTunes playback tests. Judging by the Comsumer Reports tests though, they would get a shift of 6+ hours from test to test on the 2016 model.
But the trouble with trying the same thing for the Mac is the wider variety of software people run on macOS. Third-party software may not have got any more efficient, meaning the battery doesn't last as long.
But if you stick to Mail.app and Safari then, in theory, you'll get the expected battery life.