The half marathon is running's grand doorway: serious enough to train for, human enough to achieve in 12 weeks. The calendar near you, the plan you can export to your calendar and the pace table for your goal — steady if it is your first, with a finishing kick if you are chasing a PR.
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Countdown by phases, paces, zones, nutrition and bib — everything that separates registering from crossing the finish line. Come back every week: your plan lives here.
A page with distances, elevation profile, corrals and chip timing; registrations without abusive fees and results that feed your runners' medal case — so they come back every edition.
Medio Maratón la Capital del Deporte
International data from AIMS World Running · 120+ countries · updated every 24h
21K readiness check · 4 questions · ~1 min
Answer 4 quick questions to find out if you should start now — or build 4–8 weeks of base first.
1How many km do you run per week right now?
2What was your longest run last month?
3How long have you been running regularly?
4What is your 21K goal?
Pick your goal and take the splits for every timing mat. If it's your first 21K, run even; if you already own the distance, start conservative and close the second half faster — that's how records are run.
5:41/kmsteady all 21.1 km
Your watch at every timing mat
Km 5
28:26
Km 10
56:53
Km 15
1:25:19
Km 20
1:53:45
Finish 21.1
2:00:00
With a negative split you start ~6 s/km slower and make it all back in the second half (halves of 1:01:00 and 59:00).
Download your pace band for race day
Wrist strip with your 2:00 splits · km checkpoints · pace in min/km · wear it on your wrist or share it online
NTL dark background — great for Strava and Instagram
Share your goal before the race
1080×1080 card ready for Instagram, Stories or WhatsApp — committing to your goal publicly boosts your chances of hitting it.
Carry your pace band in Google Wallet
Your splits always at hand, no internet needed on race day. Works on Android and iPhone.
Carry your pace band in Apple Wallet
Native iPhone pass — works without internet on race day. Your splits always in sight from the lock screen.
How does your goal time rank vs all global half marathon finishers?
You'd beat
25%
of all finishers
You're in the
TOP 75%
globally
Distribution of all half marathon finishers · your position
🏁Finishing is winning — you'll be ahead of many!
Source: RunRepeat 35M+ race results (2024). Overall median: 2:15:00.
Training zones · Jack Daniels method
Not every run is at race pace — running everything at the same pace is the mistake behind most injuries and plateaus. The Jack Daniels method defines 5 exact zones based on your aerobic capacity (VDOT).
Your VDOT
36.5
Functional VO₂max
Goal: 2:00:00 · Target pace: 5:41/km
VDOT is your functional VO₂max in running: the higher it is, the more efficiently you turn oxygen into speed. Tap each zone to see which sessions to do and when in your 12-week plan.
Daniels-Gilbert formula (Oxygen Power, 1979) — the global standard for middle- and long-distance planning. Paces are valid on flat terrain; on steep climbs/descents adjust ±10–20 s/km.
Log your weekly km in the Weekly Pulse to get a finish time prediction based on your training history.
→ Go to weekly pulse4 phases · personalized intensity & volume · Carmichael 2024 · Hackney 2020
Enter the first day of your last cycle to see your personalized training plan
All 4 phases
This module is for guidance only. Cycle length and phase transitions vary between people. Consult your healthcare provider for medical advice.
Training · Taper science
The half marathon taper is shorter than the marathon's — but more intense. You don't lose fitness in 2 weeks of taper. You gain it.
10-14 días
21K taper duration
2-3%
performance gain
78%
runners with 'taper madness'
21K vs Marathon taper — the key difference
21K
Marathon
The half marathon is raced at 80-90% VO₂max — you must touch that intensity zone during taper so the nervous system stays primed for race pace.
Weekly plan (weeks 11-12)
25-40% volume cut. Quality sessions: keep intensity, reduce duration.
M
6 km easy
T
HM-pace quality
W
5 km easy
T
5 km easy
F
Rest
S
8 km easy
S
Rest
Easy
⚡ Quality
Strides
Rest
The final 7 days — day by day
The 7 nevers — this week
New shoes — only wear what you trained in (40-50 km minimum)
New food or gel — everything on race morning must have been tested in training
Heavy lifting the last 7-10 days — DOMS peaks exactly on race day
Extra cardio to compensate for volume cut — it's different fatigue, not recovery
Alcohol — dehydrates, breaks glycogen synthesis, and destroys REM sleep
Standing for hours at the expo — 2-3h walking = real leg fatigue
Starting the first 5 km faster than planned pace — the mistake that ruins the most 21Ks
Nutrition for race week: nutrition plan → · Track your 12 weeks: weekly pulse → · Race day checklist: race kit → · Something hurts? injury guide →
90%+ run positive split — the wall is mental before it's physical
"Every step brings me closer"
Your only goal: cross the finish line. The medal doesn't care about time.
Lie down comfortably. Close your eyes and start at the start line — hear the ambient noise, feel the morning chill, smell the asphalt.
Mentally run the first 5 km at easy pace: smiling, loose body, controlled breathing. Feel how the legs respond.
Reach km 15-18 — the hardest moment. Visualize the discomfort ARRIVING and see yourself MANAGING it: instructional mantra, tall posture, short quick steps. Don't imagine it disappearing; imagine you're pushing through it.
Cross the finish line in your mind. Feel the pride, the medal, the faces of the people waiting.
Instructional cues outperform motivational ones at the wall (Hatzigeorgiadis 2011). Focus on FORM, not on suffering. Chunk: only think to the next km marker.
Your personal mantra appears on the shareable card below. Research shows mantras work best when rehearsed in training — add yours now.
Share the night before or at the start line — public commitment improves adherence
Race day: if the wall hits around km 15 →
Wall ProtocolWhen your body hits crisis mode, pick your symptom → 3 concrete steps.
Your goal — protocols adapt per pace group
"Peak discomfort has arrived. The feeling does NOT get worse in the last 4 km — only time passes." — Tucker et al. 2006
Read before the race — use as a mental reference at km 15-18.
Related: Mental prep · Nutrition · Heat adjustment
Gear · Shoes
The 21K is more intense per km than the marathon — you run at 85-92% of your VO₂max, not 75-80%. That changes which shoe you need. The classic mistake is the same: debuting shoes on race day, or wearing the same worn-out pair from your last 6 months of training.
Training shoe
Handles 80-90% of your volume: the 40-50 weekly km of easy runs, light tempo and the long run of the week. More cushioning, more durability, more affordable. It should feel comfortable from km 1 through km 18.
Racing shoe
For the Peak-phase tempos (weeks 9-11) and race day. More responsive, lighter. The weight difference shows at 21K pace — not at easy pace.
Only have budget for one pair? For your first 21K, training and racing in the same pair (well broken in, not excessively worn) is perfectly valid. The second pair — the racing shoe — is the upgrade worth making for your second or third half marathon. Plenty of runners have gone under 2:00 in their only training pair.
Your racing shoe goes in the race day bag — see the full checklist → · To match your pace to your shoes on race day: pace table →
Training · Injury prevention
25-40% of 21K training plans get interrupted by injury. The 5 most common injuries in half-marathon runners — how to recognize them, prevent them, and what to do when they show up before they end your training.
25-40%
of plans interrupted by injury
80%
are preventable with strength + protocol
10%
rule for max weekly increase
Quick check · How are you today?
1. Do you feel pain anywhere specific right now? (not general fatigue)
The golden rule: soreness vs. injury
Normal DOMS (muscle soreness): diffuse, often bilateral, appears 12-48h after the session, and RESOLVES in the first 5-10 min of warmup. Injury signal: focal pain, one-sided, during or immediately after the session, that PERSISTS or WORSENS as you warm up, or that makes you change your gait. When in doubt, apply the warmup test: run 10 min easy — if it eases, you can continue with caution; if it stays or gets worse, stop for the day.
Race week: can I run through it?
The 5-day taper naturally reduces symptoms 20-30% — reassess Wednesday of race week, not Sunday. Guideline: if pain is ≤3/10, eases during warmup, and doesn't change your gait → you can race. If pain is >3/10, persists, or makes you compensate → the risk of turning an injury into something that sidelines you for 6-12 weeks isn't worth it.
The right shoes prevent 60% of these: shoe guide → · Already injured? post-race recovery → · Strength exercises: weekly plan → · Track your training weeks: weekly pulse →
The 21K runs at 85–92% VO₂max — heat builds faster than in the marathon. Enter conditions to get your adjusted pace and IAAF risk flag.
Uses your location + race date (set in 'Ready for the 21K plan?') · Open-Meteo open data · no account needed
Your target time
Above optimal range. Small preventive adjustment; slower runners and masters carry higher risk.
Target pace
5:41
/km
Adjusted pace
5:46
/km
Slowdown
+5s
+1.5%
Adj. finish time
2:01:46
Hydration target: ~1300 ml/hr
Drink at every station even if you don't feel thirsty
Drink at EVERY water station available
Wear a cap and light clothing in direct sunlight
Pace adjustment in the first 5K saves energy for km 15-18
First gel at 40 min (before you feel you need it)
| Flag | WBGT | Recommendation |
|---|---|---|
| White | < 10°C | Cold risk; layer up |
| Green | 10–17.9°C | Ideal; no adjustment |
| Yellow | 18–22.9°C | Caution; minor adjustment |
| Red | 23–27.9°C | High risk; reduce pace |
| Black | ≥ 28°C | Extreme; consider cancelling |
WBGT: Stull 2011 wet bulb + solar correction +2°C. Pace multiplier: Cheuvront & Haymes 2001 + Pfitzinger tables. Flags: IAAF Road Race Medical Guidelines + ACSM Position Stand. Hydration: ACSM/Precision Fuel.
Altitude reduces VO₂max — know your real adjusted pace before arriving.
Your goal time
Race altitude
2240 mYour training altitude
0 mAcclimatization
Target pace
5:41
min/km
Adjusted pace
6:23
min/km
Target time
2:00:00
Adjusted time
2:14:44
+41.9 sec/km
+14:44 total · 12.3% slower
At 2240m (2240m above your training base), VO₂max decreases approximately 14.1%. At 21K intensity (~87% VO₂max), this becomes a 12.3% pace adjustment. Wehrlin & Hallén 2006.
• 24-72h window: the worst time to race at altitude. Arrive same morning (within 12h) OR 4+ days before for partial adaptation.
• Start conservatively — it is easy to go out at sea-level pace and blow up at km 8. Hydration increases at altitude; drink 10-15% more than usual.
Science: Wehrlin & Hallén 2006 · Pugh 1967 · Daniels & Oldridge 1970. Formula: −6.3% VO₂max per 1000m above training altitude, scaled to 87% VO₂max (HM intensity). Acclimatization: Levine & Stray-Gundersen 1997.
On race day, share your bib number with your running club and family before heading out to run — the moment Mariana looks forward to every edition.
Enter your bib number to download
Share with family and friends the exact time you'll hit each timing mat — no app, no live tracking. Jorge takes his family to the right km; Mariana sends the link to her running club.
km 3
+17 min
km 5
+28 min
km 8
+45 min
km 10
+56 min
km 13
+1:13h
km 15
+1:25h
km 18
+1:42h
km 20
+1:53h
FINISH
+2:00h
* Times assume even pacing. May vary ±5 min depending on the chip and the event course.
Voice cheer
Record a cheer message → pick the timing mat → the audio plays on its own right when your runner passes. Nothing to install, nothing to touch on race day.
Estimated time: 08:25 · 1h 25min after the gun
Tip: record before heading to your spot on the course. The phone plays it on its own; you can be cheering live while the audio plays as backup.
Race day is won the week before. Here is the full timeline, what you will find on course and the gear bag checklist — open it on race day to confirm you are not forgetting anything.
Your timeline
Days before
Pick up your race packet at the expo
The expo runs 1–2 days before. Bring your confirmation + ID. You get: bib, chip, shirt and official bag. Check it at home that same night.
Night before
Lay everything out and fuel up
Carb dinner (pasta, rice, potato). Pack your full bag. Set your alarm with a buffer. Agree on a meeting point with your family. Sleep 7–8 h.
Race morning
Wake up 3 h before the start
Light breakfast 2 h before (oatmeal, banana, toast). Get to the venue 60–75 min early. Race day traffic and transit always throw a surprise.
At the venue
Gear check and corral
Drop your bag at gear check. Enter your assigned corral 30 min before. Easy 10 min jog to activate. Share your bib number with family for live tracking.
After the finish
Medal, recovery and family
Take your medal, water and fruit. Pick up your gear bag. Family meeting point: agree on it BEFORE — no signal at the finish. Walk 15 min, do not sit down right away.
What you will find on course · typical 21K
Km 3–4
1st water
Km 7–8
Water + gel
Km 10–11
Halfway
Km 14–15
Water + gel
Km 18–19
Last water
Km 21.1
Finish!
Timing mats and aid stations vary by event. Check your race's official course map at the expo or on the event page.
Gear bag checklist
Your progress is saved on this device. Open this page on race day to confirm you have everything.
Science-based warmup protocol matched to your goal time.
Why it matters
A warmup raises core temperature to ~38.5°C, primes VO₂ kinetics (Bishop 2003) and activates fast-twitch fibers. Without it, you spend the first 2–3 km "warming up on the course" — precisely when the race position is being decided. The optimal protocol depends entirely on your goal pace: faster runners need more warmup; beginners need less.
Select your goal
Light 12-min warmup — more than enough for the 80% VO₂max of this pace.
Timing: arrive at the venue
Dynamic mobility
Short jog (800m)
1–2 × strides (60m)
Active walk to corral
Bishop 2003 (Sports Med) · Hajoglou et al. 2005 (EJAP) · Burnley et al. 2005 (J Physiol)
Nutrition · 21K
The right gels and hydration can cost you or hand you 5 minutes. Build your plan by goal time and practice it before race day.
Your goal finish time
Plan for 2:00 · 120 min total
Your route km 0 → 21
Step-by-step plan
About gels
Always take them WITH water — on their own they're too concentrated and can cause GI distress. Train with the same brand you'll use on race day.
About caffeine
It takes 30–60 min to kick in. Only if you already use it regularly — if you're not a coffee drinker, it can give you palpitations. Skip it if you have a sensitive stomach.
Share your fueling plan
Generate your personalized card with the gel plan for your 2:00 goal. Ready to share on Stories, WhatsApp, or tape to your hydration pack.
Plan based on Precision Fuel & Hydration / Science in Sport 2025. Every runner is different — adjust based on your training.
Save your finish time, see if you beat your best, and generate a card to share on social. No sign-up — it's stored only on your device.
Connect Strava and NTL reads your half marathon history automatically — no typing.
Connect with StravaConnect Polar Flow and NTL reads your half marathon history automatically.
Connect with PolarConnect Suunto and NTL reads your half marathon history automatically.
Connect with SuuntoEnter your official splits and see where you gained or lost time vs your goal
Goal time
Target pace: 5:13/km
Official cumulative times — format h:mm:ss or mm:ss (e.g. 45:30 or 1:52:10)
Who runs the most evenly-paced 21K? Best wall index (closest to 1.00) wins.
Join the ranking
Analyze at least one race in the Splits Analysis section first to unlock the ranking.
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Training sessions prescribed from your splits history. The plan adapts to your wall index.
Analyze at least one race in #splits to get your personalized training prescription.
→ Analyze my splits firstTell the community how your race was — organization, course, and on-course support.
After your race, rate your event here and generate a shareable card.
Your complete season at a glance — race history, training km, and global percentile.
Complete your first half marathon and save your time in the Results section to see your season review.
Generate a link with your 21K history — your friend opens it and you both see who improved the most.
First add at least one result in the 'Your result' section above, then come back here to generate your comparison link.
Gather your running club's comparison links (up to 12 members) and see who dropped the most time on their 21K. The captain generates a club URL to share with everyone.
Paste each member's comparison link (one per line, up to 12):
Tip: each member goes to their 'Compare your progression' section and copies their link. You collect all of them here.
How it works
0 registration required. Histories are encoded in the URL — no server, no account.
Who dropped the most time from their first 21K to their current PR? Opt in to appear — you choose your display name.
Sign in to join the ranking
Your improvement history is saved on your device. Sign in to share it with the community.
Sign inOpt-in only · No full name · No GPS data · Leave anytime
Every 21K you finish adds to your medal showcase and your streak of running years. The medal is earned at the finish line; the streak is earned by coming back.
View my medal case and streak →