Suggested day hike ratings would fall into the following levels:
Easy: Up to 5 miles and less than 1000 ft total elevation change. Suitable for beginning hikers.
Medium: Between 5 to 10 miles with possible total elevation change in the 1000-1800 ft range. Good for an experienced hiker
Hard: Over 10 miles with elevation change of 1800-2500 ft. Only for the experienced hiker in excellent condition.
Subjective (up or down) to other factors as ongoing trail condition, water crossings, and hiking speed.