With any airline, you must ask how strict is Delta on carry-on size? Are they like United's carry-on size or American Airlines' carry-on size?
Here are some guidelines to abide by with Delta carry-on size baggage. These guidelines will help you to avoid any unnecessary baggage fees.
Delta is like many of the American branded airlines with a baggage size limit of 22″ x 14″ x 9″, or 56 x 35 x 23 cm.
You can add one personal item to your trip with your carry-on. The personal item can consist of a laptop bag, book bag, or purse.
Make sure that the liquids are in a see-through resealable quart-size bag, and the liquids do not exceed 3.4 ounces or 100 milliliters of volume.