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Half Marathon Pace
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⚠️ Disclaimer: Pace calculations use the official World Athletics half marathon distance of 21.0975 km. Race time predictions use the Riegel formula (exponent 1.06) and assume adequate race-specific training. Training paces are estimates based on Daniels Running Formula and should be adjusted to individual fitness level.
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Sources & Methodology
Half marathon distance verified by World Athletics. Race predictor uses Riegel (1977) formula. Training paces from Daniels Running Formula (3rd Ed.).
World Athletics — Official Half Marathon Distance: 21.0975 km = 13.1094 miles
Official half marathon distance per World Athletics rules. All pace calculations in this calculator use exactly 21.0975 km. Pace per km = goal time / 21.0975. Pace per mile = goal time / 13.1094. This ensures precision to match official race results and GPS watch data.
Daniels, J. (2014). Daniels Running Formula, 3rd Edition. Human Kinetics.
Source for training pace zone recommendations. Easy pace = goal pace + 75-90 sec/mile. Tempo pace = goal pace minus 15-30 sec/mile. These zones form the basis of the training pace table in this calculator and are the standard reference for distance running programs globally.
🧮 Formulas Used (All Verified)
Pace/km = Total time (sec) / 21.0975
Pace/mi = Total time (sec) / 13.1094
Speed = 21097.5 (m) / Total time (sec) x 3.6 (km/h)
Riegel race predictor: T2 = T1 x (D2 / D1)^1.06
Distance: 21.0975 km = 21,097.5 m = 13.1094 miles (World Athletics official). Riegel formula (1977): exponent 1.06 accounts for increasing difficulty of longer distances. Training paces derived from Jack Daniels Running Formula (2014).
✓ All formulas verified against cited sources — Last reviewed April 2026
Half Marathon Pace Calculator — Complete Race Planning Guide
The half marathon is one of the fastest-growing road race distances in the world, with over 2 million finishers annually in the United States alone. At 21.0975 km (13.1 miles), it sits in a unique position — long enough to require serious endurance training but short enough to be achievable for most recreational runners within 12-16 weeks of preparation. Knowing your exact required pace is the most important piece of race day planning.
Half Marathon Pace Chart — Common Goal Times
| Goal Time | Pace / KM | Pace / Mile | Speed (km/h) | Level |
|---|---|---|---|---|
| 1:10:00 | 3:19/km | 5:20/mi | 18.1 | Elite |
| 1:20:00 | 3:47/km | 6:06/mi | 15.8 | Very strong competitive |
| 1:30:00 | 4:15/km | 6:51/mi | 14.1 | Competitive amateur |
| 1:45:00 | 4:58/km | 8:00/mi | 12.1 | Strong recreational |
| 2:00:00 | 5:41/km | 9:09/mi | 10.5 | Good recreational (common milestone) |
| 2:15:00 | 6:24/km | 10:18/mi | 9.4 | Average (US median ~2:10) |
| 2:30:00 | 7:06/km | 11:27/mi | 8.4 | Recreational/beginner |
Training Paces for Half Marathon Preparation
All training paces for half marathon preparation are derived from your goal race pace (GP) using the Daniels Running Formula system. The five key zones and their purpose:
- Easy runs (E pace): GP + 75-90 sec/mile. Constitutes 70-80% of total training volume. Builds aerobic base, fat oxidation, and mitochondrial density without accumulating fatigue.
- Long runs: GP + 60-75 sec/mile. Weekly long runs of 18-22 km are the single most important half marathon training stimulus. Builds specific endurance and glycogen storage capacity.
- Tempo runs (T pace): GP - 15-30 sec/mile. 20-40 minute continuous efforts at lactate threshold pace. Critical for half marathon performance — the half marathon is heavily dependent on threshold capacity.
- Half marathon pace intervals: Exactly goal race pace. 2-4 mile repeats with short recovery. Trains neuromuscular and metabolic efficiency at race intensity.
- Speed work (I pace): GP - 40-60 sec/mile. 800m-1200m intervals for VO2 max development. Raises the ceiling that limits all other training zones.
The 2-Hour Half Marathon — What It Takes
The sub-2-hour half marathon (pace: 5:41/km or 9:09/mile) is the most common recreational milestone in distance running. It places a runner in approximately the top 40-50% of most community half marathons and is achievable for most runners with 16-20 weeks of structured training:
To break 2 hours in the half marathon: You need to maintain 5:41/km for 21.0975 km. Typical weekly training volume to support this: 35-45 km per week, including one weekly long run reaching 18-20 km, one tempo run of 5-7 km at 5:11-5:26/km, and two easy runs. Most runners with a comfortable 10K time under 55:00 have the aerobic base to target sub-2:00 with adequate training. The Riegel formula predicts that a 25:00 5K runner can achieve approximately 1:56-1:57 in the half marathon with appropriate long run preparation.
Frequently Asked Questions
5:41 per kilometer or 9:09 per mile for the full 21.0975 km. To build in a small buffer, target 5:38-5:39/km or 9:04-9:06/mile. This is the most common recreational milestone. Click "Sub-2:00" above for your complete split table, training paces, and race predictions based on a 2:00:00 goal.
A half marathon is exactly 21.0975 kilometers = 13.1094 miles (commonly rounded to 13.1 miles). It is exactly half of the marathon (42.195 km). On a 400m track, a half marathon is approximately 52.7 laps. This distance uses World Athletics official measurement for all pace calculations in this calculator.
Under 1:30 = Elite. 1:30-1:45 = Very strong competitive amateur. 1:45-2:00 = Good recreational. 2:00-2:15 = Average experienced runner. 2:15-2:30 = Average for all finishers (US median approximately 2:10 men, 2:22 women). Over 2:30 = Recreational beginner. Any finish of a half marathon is an achievement. Use the quick goal buttons above to plan toward your next milestone.
Sub-1:45 requires faster than 4:58/km or 7:59/mile. Exactly 1:45:00 = 4:58.5/km or 8:00.2/mile. This is a competitive recreational level, typically placing runners in the top 20-25% of community half marathons. Training requirement: 35-45 miles per week, including tempo runs at 4:28-4:43/km and weekly long runs of 18-22 km. Click "Sub-1:45" above for your complete plan.
Pace per km = total time in seconds / 21.0975. Pace per mile = total seconds / 13.1094. Example for 2:00:00 (7200 sec): 7200 / 21.0975 = 341.3 sec/km = 5:41/km. 7200 / 13.1094 = 549.2 sec/mi = 9:09/mile. Enter any goal time above for instant calculation of pace, splits, training zones, and race predictions.
Use the Riegel formula: T2 = T1 x (D2/D1)^1.06. For a 25:00 5K: T2 = 25 x (21.0975/5)^1.06 = 25 x 4.656 = 1:56:24. For a 22:00 5K: 1:42:26. For a 20:00 5K: 1:33:07. These assume adequate long run training. Our calculator provides Riegel predictions for all race distances automatically when you enter your goal time.
Men: 57:31 by Jacob Kiplimo (Uganda), Lisbon, November 21, 2021 — approximately 2:44/km. Women: 1:02:52 by Letesenbet Gidey (Ethiopia), Valencia, October 24, 2021 — approximately 2:59/km. World records are run on certified courses with pacemakers and ideal conditions. These represent the absolute ceiling of human half marathon performance.
Beginner (first half marathon): 12-16 weeks. Intermediate (has run half marathons, targeting sub-2:15): 10-14 weeks. Advanced (sub-1:45 target, 50+ km/week): 10-12 weeks. All plans include: progressive weekly long run (peak 18-22 km), one tempo run per week, and optional speed work for faster goals. Taper mileage 2-3 weeks before race day.
Half marathon pace is typically 10-20 seconds per kilometer faster than marathon pace for most runners. A 2:00 half marathon runner typically targets approximately 4:11-4:15 in the full marathon. The half marathon can be run at a significantly higher percentage of VO2 max because there is no glycogen depletion risk ("hitting the wall") that constrains marathon pacing.
3-4 hours before: Carbohydrate-rich meal (oatmeal, pasta, rice) — 400-600 calories. 1 hour before: Light snack if needed (banana, energy bar) — 100-200 calories. Day of race: Only familiar foods — never try anything new. During the race: One gel or energy chew around km 10-14 for races over 1:45. Faster runners (sub-1:30) may not need mid-race nutrition due to shorter duration.
Negative splits means running the second half faster than the first. For a half marathon: run km 1-10 slightly slower than goal pace, then accelerate in km 11-21. Research consistently shows even or slight negative splits produce the best finish times. Most common mistake: starting 10-15 sec/km too fast in the first 3-5 km, leading to significant slowdown in km 14-21. Start your first km 5-10 sec slower than goal pace to settle in. Use the Negative Splits option above to generate a strategic split table.
From your goal pace (GP) using the Daniels system: Easy runs = GP + 75-90 sec/mile (80% of training volume). Long runs = GP + 60-75 sec/mile. Tempo = GP minus 15-30 sec/mile (lactate threshold, most important session). Half marathon pace intervals = exactly GP. Speed work = GP minus 40-60 sec/mile. The calculator above generates all five zones automatically when you enter your goal time — scroll to the training paces section below your results.
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