Here's the thing nobody selling a climb wants to say out loud: there's no audited summit rate for Kilimanjaro. Not for the mountain, and not for any operator on it.
Where the numbers come from
Operators count their own climbers and publish their own figure. Nobody checks it. There's no independent body collecting summit data, no standard for what counts as a success, and no rule about whether reaching Stella Point at 5,756 metres counts the same as reaching Uhuru at 5,895. So when you see 98 percent on a website, you're reading a marketing claim rather than a statistic. Our own previous site carried one of those claims. We took it down rather than try to stand it up.
What the number would measure anyway
Even an honest figure would mostly tell you who an operator sells to. A company running only eight-day Lemosho climbs for well-prepared trekkers will beat one running five-day Marangu for anyone who pays, and that's a fact about their customers rather than their guiding.
What actually changes your odds
Four things, roughly in this order.
Days on the mountain. The single biggest factor. Longer routes let you acclimatise, and acclimatisation is the whole game.
Pace. Pole pole means slowly in Swahili, and you'll hear it a few hundred times. It isn't a catchphrase. Walking slower than feels natural is how you arrive at the top camp with something left.
Drinking and eating. Three to four litres of water a day, and eating after you've lost interest in food. Dehydration produces symptoms that look exactly like altitude sickness.
Whether your guide is watching you. A guide who checks on you twice a day, and who's willing to tell a paying client to go down, is worth more than any number on a brochure.
Better questions than 'what's your success rate'
Ask how many guides come along for your group size. Ask whether they carry a pulse oximeter and bottled oxygen, and what happens if someone has to descend in the middle of the night. Ask how many days, and at what altitudes you sleep. Those answers you can check against the itinerary. A percentage you can't check against anything.
So what does happen?
Most people who take a seven- or eight-day route, walk slowly, drink enough and listen to their guide stand on the summit. Some don't, and it's very often not the person you'd have predicted. Turning around isn't a failure of character. It's a decision, usually the right one, and the mountain stays where it is.
Where the mountain-wide guesses come from
You'll see a figure of around two-thirds quoted for the mountain as a whole. It comes from informal park and operator estimates rather than from anybody counting, and it lumps a five-day Marangu climb together with a nine-day Northern Circuit, which is like averaging a sprint and a stroll. Treat it as a rough sense of scale, not a number to plan around.