What each of the four days looks like, where you camp and why operators give different distances.
The classic 4-day Inca Trail is 42 to 46 km — 26 to 29 miles — from Km 82 (2,720 m) to Machu Picchu (2,430 m), depending on who measures it. The listings and operator sites we checked publish four different totals: 42 km, 43 km, 45 km and 46 km. None of them says where its count starts or stops, so the gap is in the measuring, not the route: every classic 4-day trek walks the same trail from Km 82 through the Sun Gate to Machu Picchu. The one number nobody disputes is the top of the trail: Dead Woman's Pass, 4,215 m (13,828 ft), on day two.
Day by day, the shape is the same on every tour. Day one is the gentle one: about 12 km from Km 82 along the Urubamba river past the terraces of Llactapata to the first camp — Wayllabamba at 3,000 m on most treks, Ayapata at 3,300 m on the recommended one. Day two is the test: 10–11 km, of which the first 7 are a climb of roughly 1,200 m to Dead Woman's Pass, then a steep 3 km descent to Pacaymayo at 3,600 m. Day three is the longest and, most people say, the most beautiful: around 16 km over the second pass (4,000 m), past Runkurakay, Sayacmarca and Phuyupatamarca, and down a long stone staircase into cloud forest to Wiñay Wayna at 2,650 m. Day four is short — 5 to 9 km depending on the count — a pre-dawn start, the Sun Gate at about 6:30 AM, and the walk down into Machu Picchu.
What the miles don't tell you. Distance is not what makes this trek hard; altitude and stairs are. Day two gains more height than the whole rest of the trail, and day three descends more than 1,300 m on original Inca steps, which is where knees, not lungs, complain. Trekking poles are in the price on none of the sixteen treks — nine listings rent them or sell them as an add-on — and they are the single cheapest upgrade you can make.
Daily distances differ by operator. One plan walks 12, 11, 16 and 6 km; another 11, 10, 16 and about 9; a third camps further up on day two and walks 14, 16, 10 and 5. The total is the same trail — only the camps move.
Getting back on day four. After the guided visit, a bus takes about 30 minutes down to Aguas Calientes, the train about an hour and a half to Ollantaytambo, and a bus or van another hour and a half to two hours to Cusco. Most treks drop you at your hotel in the evening.
The top of the trail: roughly 1,200 m of climbing in the first 7 km of day two.
The classic Inca Trail takes four days and three nights, walking from Km 82 to Machu Picchu.
Day two is the hardest day of the 4-day Inca Trail.
Most 4-day treks camp at Wayllabamba (about 3,000 m), Pacaymayo (about 3,600 m) and Wiñay Wayna (about 2,650 m).
You reach the Sun Gate around sunrise on day four, after a pre-dawn start from the last camp at Wiñay Wayna.
The 4-day Inca Trail is 26 to 29 miles, or 42 to 46 km, from Km 82 to Machu Picchu.
Trekking poles aren't required, but they help most on day three's long stone descent of more than 1,300 m.
The high point of the 4-day Inca Trail is Dead Woman's Pass, or Warmiwañusca, at 4,215 m (13,828 ft), reached on day two.
You get back to Cusco by bus, train and road on the evening of day four.