You’ve probably heard friends talk about running a half marathon, or maybe you’re considering signing up for one yourself. Whatever brought you here, the first question is almost always the same: how far is a half marathon? The answer is both simple and precise — exactly 21.0975 km (13.1094 miles) — and once you know what that distance really means in terms of time, training, and effort, everything else falls into place.
Half marathon distance in kilometers: 21.0975 km ·
Half marathon distance in miles: 13.1094 mi ·
World record (men): 57:31 (Jacob Kiplimo, 2021) ·
World record (women): 1:02:52 (Letesenbet Gidey, 2021) ·
Average finish time (all finishers, US): 2:00:00–2:15:00 ·
Typical walking time: 3–4 hours
Quick snapshot
- Half marathon is exactly 21.0975 km (World Athletics (governing body))
- World records: 57:31 (men), 1:02:52 (women) (World Athletics)
- Walking a half marathon takes 3–4 hours (The Running Channel (running education platform))
- Exact average finish time varies significantly by race and demographic
- Global number of half marathon finishers is not centrally tracked
- World records have remained unchanged since 2021
- No major rule changes from World Athletics
- More runners are using half marathons as a stepping stone to full marathons
- Training plans are increasingly data-driven and personalized
The half marathon sits at a sweet spot: it demands serious preparation but remains achievable for most fitness levels. Here’s how the numbers stack up.
| Metric | Value |
|---|---|
| Distance (km) | 21.0975 |
| Distance (mi) | 13.1 |
| World record (men) | 57:31 |
| World record (women) | 1:02:52 |
| Average finish time | 2:00–2:15 |
The implication: even average performers are covering distance at a pace most people would consider a solid jog.
How many km is a half marathon?
The half marathon distance is defined by World Athletics (the international governing body for track and field) as exactly 21.0975 kilometres. That figure is not arbitrary — it is precisely half of a full marathon (42.195 km). In practice, most race organisers round the distance to 21.1 km on signs and promotional material, and the imperial equivalent is commonly given as 13.1 miles.
Half marathon distance in miles
- 13.1094 miles is the exact conversion from 21.0975 km.
- Races and media typically round to 13.1 miles (The Running Channel (running education platform)).
- That is about 5.5 times the distance of a 5K and slightly more than double a 10K.
How does half marathon compare to a full marathon?
World Athletics notes the half marathon is exactly half the length of a marathon. The practical difference, however, goes beyond numbers: a half marathon requires less recovery time, fewer weeks of peak training, and is accessible to a much wider range of fitness levels. Many runners treat it as both a standalone goal and a stepping stone to a full marathon.
How long does a half marathon take?
Finish times vary widely depending on fitness level, age, gender, terrain, and weather. According to Runner’s World (leading running magazine), the average finish time for half marathons completed in the United States is about 2 hours and 10 minutes. In the UK, 220 Triathlon (multi-sport training resource) reports an average of 2:02:43, with men averaging 1:55:26 and women 2:11:57.
Average half marathon time by age and gender
- Men aged 20–30 often finish between 1:40 and 2:00.
- Women aged 30–40 typically finish between 1:50 and 2:15.
- Runners over 60 may take 2:15–2:45 or longer.
Factors that influence finish time (fitness, terrain, weather)
- Fitness: consistent runners with a base of 25+ km per week finish faster.
- Terrain: hilly courses add 10–20 minutes compared to flat routes.
- Weather: heat above 25°C can slow pace by 30 seconds per mile.
What is a good half marathon time?
“Good” depends on your goals. For amateur runners, a sub‑2‑hour finish is a widely respected benchmark — it signals consistent training and a well-paced race. A time of 1:35–1:50 is considered very good for age‑group competitors. At the elite level, the world records — World Athletics lists 57:31 for men (Jacob Kiplimo, 2021) and 1:02:52 for women (Letesenbet Gidey, 2021) — represent the absolute limit of human performance over 13.1 miles.
Sub‑2‑hour half marathon: what pace is needed?
To break two hours, you need an average pace of 9:08 per mile or 5:40 per kilometre, as The Running Channel explains. That is a steady jog for most fit recreational runners, but maintaining it over 13.1 miles requires specific training.
Good half marathon time by age group
- Under 30: under 1:45 is good; under 1:30 is excellent.
- 30–40: under 1:50 is good; under 1:40 is excellent.
- 40–50: under 2:00 is good; under 1:45 is excellent.
- 50+: under 2:15 is good; sub‑2:00 is outstanding.
For most runners, a sub‑2‑hour half marathon is the gold standard. To hit it, you need to train consistently, run at 9:08 per mile, and manage pacing. Recreational runners aiming for 2:00–2:15 should focus on building endurance rather than speed.
Can you walk a half marathon?
Yes — walking a half marathon is entirely achievable for most people, provided they prepare properly. At a normal walking pace of about 3 to 4 miles per hour, you can expect to finish in 3.5 to 4 hours. Many half marathon events allow walkers, but check the race’s cutoff time — some require a 3‑hour finish.
Average walking time for 13.1 miles
- Brisk walk (~4 mph): 3 hours 15 minutes.
- Moderate pace (~3.5 mph): 3 hours 45 minutes.
- Leisurely pace (~3 mph): 4 hours 20 minutes.
Walking a half marathon is also gentler on the joints, making it a lower‑risk option for beginners or those recovering from injury.
Walking vs. running a half marathon: physical demands
- Walking burns about 1000–1300 calories over 13.1 miles; running burns 1500–2000.
- Walking causes less impact stress on knees and hips.
- Walking requires longer exposure to weather and more hydration.
Can you run a half marathon if you can run a 10K?
If you can already run a 10K (6.2 miles), you are well on your way. The Running Channel advises that runners stepping up from a 5K or 10K should allow 8 to 12 weeks of dedicated half‑marathon training. Those already training consistently may be ready in 6 to 10 weeks. The key difference is endurance — a half marathon demands more sustained effort and careful fueling.
Training plan for extending 10K to half marathon
- Build your long run by 1 mile every week, capping the increase at 10% per week.
- Run at least three times per week — one interval session, one tempo run, one long run.
- Take one full rest day per week, as The Running Channel recommends.
- Practice nutrition: carry a gel or sports drink on runs longer than 90 minutes.
- In the final 2 weeks, taper your mileage by 30% to arrive fresh.
Key differences in endurance and nutrition
- A half marathon requires more hydration: drink 500–750 ml per hour.
- Fuel intake: consume 30–60 grams of carbohydrates per hour during the race.
- Your pace for a half marathon should be about 20–30 seconds per mile slower than your 10K race pace (Runner’s World).
Runners coming from a 10K often hit the wall at mile 10. The fix: practice long runs at your target race pace and take gels early. If you skip fueling, your pace will drop by 30–60 seconds per mile in the final 3 miles.
One comparison, a few distances: here is how the half marathon stacks up against shorter races.
| Attribute | 5K | 10K | Half Marathon |
|---|---|---|---|
| Distance | 3.1 mi / 5 km | 6.2 mi / 10 km | 13.1 mi / 21.1 km |
| Typical finish time (beginner) | 25–35 min | 50 min – 1:10 | 2:00 – 2:30 |
| Training duration (from couch) | 4–6 weeks | 6–10 weeks | 10–16 weeks |
| Calories burned (approx.) | 300–400 | 600–800 | 1,200–1,600 |
| Injury risk (relative) | Low | Moderate | Moderate–High |
The pattern: each step up the distance ladder demands a disproportionate increase in training volume and recovery, making the half marathon the steepest jump from a 10K.
“A sub‑2‑hour half marathon is a great target for most recreational runners. It requires consistent training but is very achievable with a structured plan.”
“If you’ve already run a 10K, you’re 70% of the way to a half marathon. The remaining 30% is about building endurance and learning to fuel properly.”
— Certified running coach, quoted in The Running Channel (running education platform)
Confirmed facts vs. open questions
Confirmed facts
- Half marathon distance is exactly 21.0975 km (13.1094 miles). (World Athletics)
- World records: 57:31 (men), 1:02:52 (women). (World Athletics)
- Walking a half marathon takes 3–4 hours at a normal pace. (The Running Channel)
What’s unclear
- Exact average finish time varies significantly by race and demographic.
- The precise number of half marathon finishers globally is not centrally tracked.
For a deeper dive into finish times and how to train for 13.1 miles, check our detailed half marathon guide.
Frequently asked questions
Is 2 hours good for a half marathon?
Yes — a sub‑2‑hour half marathon is a strong benchmark for recreational runners. It indicates consistent training and solid pacing. Many amateur club runners aim for this time as a primary goal.
What pace do I need for a sub‑2‑hour half marathon?
You need an average pace of 9:08 per mile or 5:40 per kilometre. To hit that, you should be able to run a 10K in under 55 minutes and maintain your pace on long runs.
How should I fuel during a half marathon?
Consume 30–60 grams of carbohydrates per hour — typically a gel or sports drink every 30–40 minutes. Also drink 500–750 ml of water per hour depending on heat and sweat rate.
What is the most common injury in half marathon training?
Runner’s knee (patellofemoral pain) is the most frequent issue, often caused by increasing mileage too quickly. Shin splints and Achilles tendinitis also common. Ease up on volume if pain appears.
Can I run a half marathon without stopping?
Many runners do take short walk breaks. It is perfectly fine to walk through water stations or during tough sections. The goal is to finish — not to run every step.
How many calories do you burn in a half marathon?
A 150‑lb person burns roughly 1,200–1,600 calories over 13.1 miles, depending on pace and terrain. Heavier runners burn more; lighter runners burn fewer.
What should I eat the night before a half marathon?
Aim for a carbohydrate‑rich meal like pasta, rice, or potatoes with a moderate amount of protein. Avoid high‑fat or high‑fiber foods that might upset your stomach. Stay hydrated.
For the runner aiming to tackle a half marathon, the choice is clear: train steadily, respect the distance, and treat it as both a goal and a gateway. Whether you run it in under two hours or walk it in under four, finishing 13.1 miles is a meaningful achievement that builds confidence for whatever comes next.
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Kieran Doherty covers Westminster, Whitehall, councils, local government and institutional reporting for Civic Affairs.