I don't actually count my carbs, just avoid them, but I would think you could use some kind o APP for a mobile phone, which would keep a running total for you. You might need to use something designed for counting calories.
However, Since I rarely eat pre-made food, I'd have trouble looking up carbs on most of what Ieat. I can look up and weigh foods at home and build the info for my recipes, but that's not particularly quick.
Hana