If you're going by road and choosing the Shimla route from Delhi then it would take approximately 18 hours of driving for you to reach there if you don’t make many pit stops but that’s entirely up to you. Now, if you're taking the Manali route then at least 24 hours in the car, driving is required and you need to make a pit stop after reaching Manali or you'll be very much exhausted otherwise. The total distance between Lahaul Spiti and Delhi is 708 Kilometers if we go by the shortest route.