Half marathon · Advanced amateur

Sub-1:45 half marathon

Run 21.1 km in under 1 hour 45 minutes — 12 weeks, 5 running days a week.

12WEEKS

Twelve weeks at five days a week, building to around 60 km. At this level the aerobic base is already there and the improvement comes from threshold volume — more minutes spent at the pace you can just about sustain for an hour. Two quality days, one long run with goal-pace work in it, and honest easy running in between.

SOURCE·Race calendars + pace computation·Schedule constructed from mainstream distance-running practice, not a single published programme·REVIEWED JUL 2026

On the entry line: A half marathon around 1:50–2:00, or a 10K under about 48 minutes.

What the goal costs per kilometre

Pace needed

4:58/km

Train and pace at

4:55/km

Distance

Half marathon

Plan length

12 weeks

TEAR AT THE PERFORATION · ONE GRADUATION EVERY KILOMETRE · TALL TICKS ARE HALFWAY AND THE FINISH

1:45:00 over 21.0975 km is 4:58 per kilometre. Note that this is the same per-kilometre pace as a sub-3:30 marathon — if sub-1:45 is comfortable, that is the natural next target. Every tick, for any target, on the split calculator.

COMPUTED·target seconds ÷ official distance, then × each kilometre mark·NOT AN ESTIMATE, NOT A MODEL·WORKING CHECKED JUL 2026

The full 12-week schedule

Every session written out. Print this page — the navigation, banners and footer are all stripped from the printed version, leaving the table.

Sub-1:45 half marathon — the full 12-week schedule. 5 running days a week.
Week	Mon	Tue	Wed	Thu	Fri	Sat	Sun	Long run
1	Rest	6 × 1 km at 4:40/km, 90 s jog	Easy 8 km	25 min threshold at 4:55/km	Rest	Easy 8 km	Long run 14 km, easy	14 km
2	Rest	5 × 1.5 km at 4:45/km, 2 min jog	Easy 8 km	30 min threshold at 4:55/km	Rest	Easy 8 km	Long run 16 km, easy	16 km
3 Long run: last 5 km at 4:55/km	Rest	3 × 3 km at 4:55/km, 3 min jog	Easy 8 km	2 × 15 min at 4:50/km	Rest	Easy 8 km	Long run 17 km, easy	17 km
4 Cutback week	Rest	10 × 600 m at 4:30/km, 90 s jog	Easy 7 km	25 min threshold	Rest	Easy 7 km	Long run 14 km, easy	14 km
5 Long run: last 6 km at 4:55/km	Rest	4 × 2 km at 4:50/km, 2 min jog	Easy 9 km	40 min threshold at 5:00/km	Rest	Easy 9 km	Long run 18 km, easy	18 km
6	Rest	12 × 400 m at 4:20/km, 75 s jog	Easy 9 km	2 × 20 min at 4:50/km	Rest	Easy 9 km	Long run 20 km, easy	20 km
7 Cutback week	Rest	5 × 1 km at 4:35/km	Easy 7 km	30 min threshold	Rest	Easy 7 km	Long run 15 km, easy	15 km
8 Long run: last 8 km at 4:55/km	Rest	3 × 4 km at 4:55/km, 3 min jog	Easy 9 km	50 min steady at 5:20/km	Rest	Easy 9 km	Long run 21 km, easy	21 km
9 Longest run of the plan	Rest	6 × 1.5 km at 4:45/km, 2 min jog	Easy 9 km	45 min steady at 5:20/km	Rest	Easy 9 km	Long run 22 km, easy	22 km
10 Taper begins	Rest	2 × 5 km at 4:55/km, 4 min jog	Easy 8 km	30 min threshold	Rest	Easy 8 km	Long run 17 km, easy	17 km
11	Rest	5 × 1 km at 4:40/km	Easy 6 km	20 min at 4:55/km	Rest	Easy 6 km	Long run 12 km, easy	12 km
12 Goal week	Rest	3 km at 4:55/km	Easy 4 km	20 min easy with 4 × 20 s strides	Rest	Easy 4 km	Race: half marathon	Race: half marathon

Quality — the session that changes your fitness. Do this one first if the week gets busy. Easy — conversational. Slower than feels right. Long run — slow, and the backbone of the plan.

SOURCE·Race calendars + pace computation·Weekly volume, cutback weeks and taper follow standard practice; not individual coaching·REVIEWED JUL 2026

How to run this plan

Threshold pace here is roughly 4:50–5:00/km. Precision matters: 20 seconds too fast turns a threshold session into a race.
Easy running at 5:50–6:20/km. At this volume, easy days that are not easy are the main cause of injury.
Strength work twice a week if you can. Sub-1:45 asks a lot of calves and hamstrings.
Sleep is a training variable at this level, not a lifestyle detail.

Strength work. Strength: 20 min of squats, lunges, single-leg calf raises, glute bridges and planks. This is the injury insurance. Add it on an easy day or straight after an easy run — never the day before a quality session. If you want the movements themselves written out, running's supporting exercises, by muscle worked and equipment needed, is the reference.

The principle underneath the table

Roughly eighty per cent of the running in this plan is easy, and that ratio is not a compromise — it is the mechanism. Easy running builds the aerobic machinery that lets you absorb the hard sessions; hard running that is not paid for by easy running just accumulates fatigue. The most common way an amateur plan fails is that the easy days creep up to a moderate pace, the hard days consequently drift down to the same moderate pace, and the runner spends twelve weeks training one gear.

The second principle is the cutback week. Volume in this plan does not climb monotonically; every third or fourth week it drops. Adaptation happens during recovery, not during the session, and a plan without down weeks is a plan that banks fatigue until something gives.

The third is the taper. The last two to three weeks reduce volume sharply while keeping a small amount of intensity. It will feel wrong. Do it anyway — nothing you run in the final fortnight can make you fitter, and plenty of it can make you tired.

Questions in the weeks before the gun

How long is the sub-1:45 half marathon plan?

12 weeks, running 5 days a week. A half marathon around 1:50–2:00, or a 10K under about 48 minutes.

What if I miss a week?

One missed week: pick the plan up where you left off, do not try to catch up by doubling anything. Two or more: step back two weeks in the schedule and rebuild. The plan is a progression, and the progression is the part that works — skipping forward to stay 'on schedule' is how people get injured in week ten.

Can I move the days around?

Yes, with one rule: keep at least one easy or rest day between the quality sessions and the long run. The days of the week are arbitrary; the spacing is not.

Is run 21.1 km in under 1 hour 45 minutes realistic for me?

A half marathon around 1:50–2:00, or a 10K under about 48 minutes. If you are some way off that, the honest answer is that this plan will not bridge the gap in 12 weeks — build the base first and come back. Put a recent race into the race time predictor to see where you actually stand.

How do I train for this in Indian heat?

Move everything to before sunrise, run the quality sessions by effort rather than pace once it is above about 25°C, and accept that summer paces are slower than winter paces at identical fitness. In the north from November to January, check air quality before every session and take it indoors when readings are bad.

Other half marathon plans

First half marathon12 weeks · 4 days a week · Beginner to intermediate Sub-2 hour half marathon12 weeks · 5 days a week · Intermediate

All twelve are listed on the training plans page.

Every time, pace and physiological figure on this site is computed from a published formula, and the formula is named and shown on the method page. Nothing here is predicted by a model you cannot check. Race details change — always confirm dates, routes and entry with the official organiser. Training guidance is general information, not individual coaching or medical advice.

SOURCE·Race calendars + pace computation·REVIEWED JUL 2026

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