Carbs in Lasagna. The favorite choice for the term Lasagna is 1 piece (1/6 of 8 square, approx 2-1/2 x 4) of Lasagna with Meat which has about 35 grams of carbohydrate. The total carbohyrate, sugar, fiber and estimated net carbs (non-fiber carbs) for a variety of types and serving sizes of Lasagna is shown below. Popular Types of Lasagna.