For a long time this has been the most popular route on Kilimanjaro, this route starts at the Kilimanjaro National Park headquarters. Famous as Coca Cola Route which means easy to hike to the Top of Kilimanjaro, but hiking up with not enough acclimations points makes this route less successful than the Machame or Lemosho routes to reach to the top of Kilimanjaro. 
Day 1: Mandara Hut - 4~5 hrs from Marangu Gate, 8km Day 2: Horombo Hut - 5~6 hrs from Mandara, 11.5km Day3: Kibo Hut - 5~6 hrs from Horombo, 10.3km 
Minimum days to hike this route is 5 days and maximum days is 6 day but clients can ask for more days, whereby they will have chance to hike up Zebra Rock and Back to Horombo for one more night, which will be helpful as acclimatization days. 
The Marangu is the oldest, most well established route. Climbers like the Marangu route because it is thought to be the easiest path on the mountain, because of it’s gradual slope, and the fact that it is the only route that offers sleeping in huts (dormitory style).
However, since many climbers choose to climb the Marangu route over five days - the minimum days required for this route -, the chance of successfully reaching the top in that time period is lower. Spending an extra acclimatization day on the mountain is highly recommended when climbing Klimanjaro using the Marangu route.
However, Team Raha recommends the other routes (Machame, Lemosho or Londorosi) over the Marangu route for several reasons: The route has the least scenic variety of all the routes because the ascent and descent are done on the same path; it is the most crowded route; and it has one of the lowest success rates if done in 5 days. Marangu is favored only during the rainy season, where the hut accommodations are better than sleeping in tents.