The most basic difference between a sweater and a sweatshirt is the way they’re made. A sweater is crocheted or knitted, whereas a sweatshirt is not. A sweatshirt is made with heavy cotton. Sweaters are meant to keep you warm in the winters. A sweatshirt is also meant to keep you warm, although that’s not its only purpose. Along with keeping one warm, they also absorb sweat as we talked about earlier in the article. This makes them a go-to choice for athletes and fitness enthusiasts.