Gather and prep all the ingredients.
Boil a large pot of lightly salted water and cook the elbow macaroni until al dente, about 8 minutes. Then, rinse the macaroni under cold water and drain well.
In a large mixing bowl, whisk together mayonnaise, sugar, vinegar, mustard, salt, and pepper until smooth. Add the drained macaroni and toss to coat evenly.
Fold in the chopped celery, onion, green bell pepper, grated carrot, and pimento peppers into the macaroni mixture.