How is an ultramarathon different from a marathon?

An ultramarathon differs from a marathon in distance, terrain, and pacing strategy. Marathons are 26.2 miles, almost always on roads, run at near-threshold pace. Ultramarathons range from 31 to 250+ miles, are usually on trails with significant elevation, and are run at a much easier conversational pace with deliberate walking on climbs. Ultras require fueling strategy (250–350 calories per hour), aid-station discipline, foot care, and, for races over 12 hours, night running and sleep strategy.

How long does it take to run an ultramarathon?

Time to complete an ultramarathon depends on distance and terrain. A 50K typically takes 4–9 hours. A 50-mile ultra takes 8–14 hours. A 100K takes 11–18 hours. A 100-miler takes 18–32 hours, with elite runners finishing in 14–18 hours and most cutoffs at 30–36 hours. 200-mile ultramarathons take 50–125+ hours and span multiple days with sleep stops.

Can a beginner run an ultramarathon?

A beginner can train for and finish a 50K (the shortest ultra) within 16 weeks if they have a marathon finish in their legs and a 25–35 mile-per-week base. Skipping straight to a 100-miler from no marathon experience is not realistic, most ultrarunners build through the distances over multiple seasons: 50K, then 50-mile, then 100K, then 100-mile. The 100-miler typically requires two seasons of accumulated ultra experience.

What was the first ultramarathon?

The Comrades Marathon in South Africa, founded in 1921, is generally considered the first modern ultramarathon, running approximately 90 km (56 miles) between Pietermaritzburg and Durban. The Western States Endurance Run, founded in 1974, is the most influential American 100-mile race and is credited with starting the modern American ultramarathon scene. The Spartathlon, run since 1983, retraces the route of Pheidippides from 490 BC.

What are the most famous ultramarathons?

The most prestigious ultramarathons in the world include the Western States 100 (California, USA), the Ultra-Trail du Mont-Blanc (Chamonix, France/Italy/Switzerland), the Hardrock 100 (Colorado, USA), Comrades (South Africa), the Marathon des Sables (Morocco), the Spartathlon (Greece), and the Tor des Géants (Italy). The Cocodona 250 (Arizona) is the most prominent multi-day ultra in North America.

How fast do you run an ultramarathon?

Ultramarathon pacing is much slower than marathon pacing. A 24-hour 100-mile finish averages 14:24 per mile across the race, including walking climbs and aid-station stops. Elite male 100-mile runners average 9:00 per mile; elite female runners average 9:30. The conversational pace test, being able to speak full sentences while running, is the most reliable pacing guide. Running too fast in the first hour is the single most common cause of ultra DNFs.

The Complete Guide Definition

What is an ultramarathon?

Short answer: an ultramarathon is any footrace longer than the marathon distance of 26.2 miles (42.195 km). The five standard distances are 50K, 50 miles, 100K, 100 miles and 200 miles and up, most of them run on trail with generous cutoffs, so finishing rather than pace is the first goal. Updated 2026.

An ultramarathon is any footrace longer than the marathon distance of 26.2 miles (42.2 km). The five canonical distances (50K, 50 mile, 100K, 100 mile, 200+) define a sport that's grown from a few hundred runners in the 1970s to a global phenomenon with tens of thousands of finishers each year.

The short answer

An ultramarathon (or ultra) is any footrace longer than 26.2 miles (the standard marathon distance of 42.2 km). The most common ultra distances are 50K (31 mi), 50 miles, 100K (62 mi), and 100 miles. Multi-day ultras at 200, 240, and 250 miles are increasingly popular. Most ultras are run on trails with significant elevation gain, though road and track ultras exist.

The five distances

From 31 miles to 250.

Ultrarunning organizes around five canonical distances. Each is a different sport, different time on feet, different fueling, different mental skills.

50 kilometer (50K), 31.1 miles. The shortest ultra. Typical finish time: 4–9 hours. Bridge from marathon racing to trail ultra. → Training plan
50 mile, 80.5 km. The first true "long day on feet." Typical finish: 8–14 hours. Real fueling and pacing required. → Training plan
100 kilometer (100K), 62.1 miles. Bridge to the buckle distance. Typical finish: 11–18 hours. Most runners experience their first night running. → Training plan
100 mile, 160.9 km. The classical buckle distance. Typical finish: 18–32 hours. The race ultrarunning is built around. → Training plan
200+ mile. Multi-day racing, Cocodona 250, Bigfoot 200, Tahoe 200, Moab 240. Typical finish: 50–125+ hours. Closer to expedition than race. → Training plan

How ultras differ

Not just longer marathons.

A marathon is 26.2 miles run at near-threshold pace on roads. An ultra is everything else.

Marathon

26.2 miles (42.2 km), fixed
Almost always on road
Minimal elevation gain
Run at near-threshold pace
Aid stations every 1–2 miles, water-only
Typically 3–6 hours
Few elite cutoffs
No drop bags, no crews

Ultramarathon

31 to 250+ miles, varied
Usually trail; sometimes road or track
Often 5,000–40,000 ft elevation gain
Run at conversational pace
Aid stations every 4–10 miles, with food
4 hours to 6+ days
Strict cutoffs, often by aid station
Drop bags, crews, pacers (varies)

A brief history

From 1921 to the modern boom.

Ultramarathon running predates the modern marathon by decades. The current global boom started in the 2000s.

1921

Comrades Marathon founded

Pietermaritzburg to Durban, South Africa. ~90 km. The first modern ultramarathon, founded in commemoration of WWI veterans. Still the largest ultra in the world by entries (over 20,000 annually).

1974

Western States 100 founded

Olympic Valley to Auburn, California (our Western States briefing). The first 100-mile foot race in modern North America, descended from the Tevis Cup horse race that ran the same trail. Created the modern American ultra scene.

1983

Spartathlon founded

Athens to Sparta, 246 km. Retraces the route of Pheidippides from 490 BC. The most historically significant ultramarathon on the planet.

2003

UTMB founded

Ultra-Trail du Mont-Blanc, Chamonix. A loop of about 170 km around Mont Blanc (174 km today). Quickly became the most prestigious mountain ultra in the world. The race that made ultrarunning a global sport.

2010s

The modern boom

Ultra finishes worldwide grew from approximately 50,000 in 2010 to over 600,000 by 2020. Social media coverage of races like UTMB, Hardrock, and Western States created a global awareness; documentaries like Unbreakable and Where Dreams Go to Die brought new runners into the sport.

2020s

The 200-mile era

Cocodona 250 (Arizona, founded 2021) brought multi-day ultra racing into the mainstream. Aravaipa Running's livestream coverage created a new viewer experience. Multi-day races now share the stage with traditional 100s as the marquee distance.

Training

How runners actually train for ultras.

Ultra training is mostly easy mileage. The training mistake most ultrarunners make is running too hard on easy days.

The 80/20 rule

About 80% of weekly running volume should be in Zone 2 (conversational pace, 60–70% of max HR). The remaining 20% is higher-intensity work, tempo, threshold, hill repeats. The 80/20 distribution is validated across nearly every endurance sport. Most amateur ultrarunners run too hard on easy days, accumulating fatigue without driving adaptation.

The back-to-back long run

The defining ultra-specific workout. A long Saturday run (18–32 mi) followed by a moderate Sunday run (10–22 mi). The point: train your legs to run after they're already tired. There is no other workout that produces this adaptation.

Race-specific terrain

Train on the surface and elevation profile of your target race. A flat-road runner training for Hardrock will under-prepare; a Western States runner training only on technical mountain terrain will lose road-running fitness. Specificity matters more than volume past a certain threshold.

Fueling rehearsal

Every long run over 90 minutes is a fueling rehearsal. Trained ultrarunners absorb 250–350 calories per hour during races. The gut is a trainable system; runners who don't fuel in training bonk in races. → Ultra fueling calculator