Everest’s 29% overall success rate is the product of decades of diverse attempts — from solo oxygen-free ascents to large commercial expeditions with full Sherpa support. In commercially supported seasons with stable weather, summit rates on the South Col route for guided clients using supplemental oxygen regularly exceed 55%. The overall 29% figure is dragged down by oxygen-free attempts (single-digit success rates), the more demanding Tibet side, and decades of historical attempts before modern equipment and forecasting existed.

How to read these numbers: Success is defined as reaching the true summit (8,849m). Data covers all permitted expeditions from both sides 1990–2025, sourced from The Himalayan Database, Nepal Ministry of Tourism records, and China Tibet Mountaineering Association data. The guided/independent breakdown reflects whether a commercial guiding contract was in place, not whether Sherpa support was used.

Everest has the most compressed summit window of any peak in this database. The jet stream must lift off the summit for a window to exist, and that window in the pre-monsoon season typically lasts 4–6 days in May. Missing it — or being trapped waiting for it — is the defining logistical challenge of a modern Everest expedition.

May accounts for over 85% of all Everest summits in the pre-monsoon season. The specific window within May — typically May 10–25 — is determined entirely by jet stream position and is impossible to predict more than 5–7 days in advance. Teams positioned and ready at Camp 4 when the window opens have consistently higher summit rates than those still on acclimatization rotations.

The South Col route’s substantially higher success rate reflects its Sherpa infrastructure, fixed rope system maintained throughout the season, and the concentration of commercial expedition support. The North Ridge is technically comparable on the upper mountain but operates with less infrastructure and no Khumbu Icefall hazard — though the Second and Third Steps present their own technical challenges.

The gap between guided and truly independent Everest attempts is the largest of any peak in this database — and the most consequential. On Everest, “guided” typically means full commercial expedition support including high-altitude Sherpa team, oxygen system management, fixed ropes to the summit, and emergency coordination. “Independent” on Everest is a genuinely different undertaking.

No other peak in this database shows a stronger correlation between prior high-altitude experience and success. The physiological demands above 8,000m are non-linear — prior summits at 7,000m do not adequately prepare a climber for the Death Zone in the way that prior 8,000m experience does.

From The Himalayan Database expedition records and post-expedition operator reports, 2010–2025, South Col route.

Everest has the most expensive and logistically complex rescue profile of any peak in this database. Helicopter access above base camp is available to approximately 6,400m on the Nepal side in favorable conditions, but above that altitude evacuation requires human carries or improvised lowering systems. True high-camp rescues are rare; most evacuations occur from Camp 2 or below.

Everest’s fatality rate of 1 in 95 is higher than any other Seven Summit but substantially lower than K2 (1 in 4). The Death Zone above 8,000m cannot be survived without supplemental oxygen by most climbers for more than a limited number of hours — oxygen system failure at high camp is effectively unsurvivable without immediate descent. Comprehensive expedition insurance with helicopter evacuation and medical repatriation cover is non-negotiable for all Everest attempts.

Everest’s success rate has improved markedly from the 1990s (15–20%) to the modern era (28–35%), driven by better weather forecasting, improved oxygen systems, fixed rope infrastructure, and the growth of commercial expeditions with experienced Sherpa support. However, the 2012–2025 period has introduced a new pressure on success rates: Death Zone crowding that costs teams critical time during narrow weather windows.

The plateau in success rates since 2012 is not a failure of improvement — it is the crowding effect offsetting continued improvements in equipment, forecasting, and Sherpa support. The 2019 season’s dramatic queue photographs brought this structural issue to global attention. Nepal has experimented with permit limits and scheduling frameworks but no structural solution has yet demonstrably improved the Death Zone crowding problem.