One slice of turkey, on average, is equivalent to about 1 ounce of meat. This number may vary slightly depending on the thickness of the slice. Deli counters, at patrons' requests, slice meat extra thin (shaved) or thick.
It is recommended that 3 to 4 ounces of turkey be used in the making of a sandwich. Assuming 1 ounce slices, this is 3 or 4 slices of turkey. There are about 29 calories in a single 1 ounce slice of turkey. This means there are an estimated 87 to 116 calories of turkey in a single sandwich, not counting the bread, vegetables or condiments.