The other thing to consider is if you use per sector logging you can just enter out and in times and it will calculate block time as well as how much of that is night (where applicable of course).
If you are with one of the airlines as ROJ suggested you can use roster buster or airline roster to import your roster into your phone/iPad/portable electronic thingie and then either app will export to logten pro so the hard work is done, all you need to do is enter sign on and off (for FDP calcs) and out and in times (I record OOOI times).
I am not a fan of their subscription model and seeing as I bought the iPad and Mac versions about 3 weeks before they moved to that model I wasn't impressed with being asked to stump up to keep using something I just bought, but they resolved that concern and the app itself is very good.