Training Plans · Half Marathon · Sub-1:20

Sub-1:20 Half Marathon Training Plan: The Semi-Elite Half Line

Sub-1:20 is the semi-elite half marathon line. 6:06 per mile for 13.1 miles. The step after sub-1:30. Demands serious mileage, threshold volume, and tight pacing. Here's the plan.

By John Farrell, Founder of Pheidi 7 min read Updated Sep 14, 2026 Training Plans · Pheidi cluster article

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Sub-1:20 is the semi-elite half marathon line. 6:06 per mile for 13.1 miles. The step after sub-1:30 isn't a step. It's a jump. Sub-1:30 requires advanced amateur fitness. Sub-1:20 requires sustained near-elite training.

For the broader half marathon picture, see the half marathon training plan guide. For the step below, see the sub-1:30 half plan.

What Pace Is a 1:20 Half Marathon?

6:06 per mile. 3:47 per kilometre. Dead-even pace for exactly 1:20:00 is 6:06.2 per mile and 3:47.5 per km, so both of those round in your favour: hold 6:06 and you finish 1:19:58, hold 3:47 and you finish 1:19:49. Note that 3:48 per km does not get there. It finishes 1:20:10.

The table below is the even-pace checkpoint sheet: what the clock reads at each marker if you run the whole race at goal pace.

Marker	Clock at 1:20:00 pace
5 km	18:58
5 miles	30:31
10 km	37:55
15 km	56:53
10 miles	1:01:02
20 km	1:15:50
13.1 miles (finish)	1:20:00

Two things that table hides. First, 1:20:00 is the number you have to beat, not hit, so the honest target is a 5 to 10 second cushion banked by 10 km rather than an exact-pace tightrope. Second, nobody runs a real course at literally even pace, so treat the checkpoints as a drift check rather than a script.

What a deficit actually costs you is arithmetic, not vibes. Twenty seconds behind the 37:55 checkpoint puts you through 10 km in 38:15, which leaves 41:45 for the remaining 11.1 km — 3:45.7 per km, faster than goal pace for more than half the race, on legs that are already behind. Sub-1:20 is still on the table there. It is just a different race than the one you planned.

Is Sub-1:20 a Good Half Marathon Time?

It is the semi-elite amateur line. Sub-1:20 puts you in front of nearly every recreational field you will ever line up in, and it is the last round-number barrier before the times that win small local races outright. The step down from sub-1:30 is 46 seconds per mile, held for 13.1 miles. That is not a sharpening block. It is a different training tier.

Prerequisites

5K under 17:30. The VDOT math: 17:30 5K predicts ~1:19 half. Most sub-1:20 runners have 5K PRs of 16:30-17:30.
10K under 36:30. The most predictive single race.
2+ halves completed. Pacing discipline at 6:06 takes experience.
Weekly mileage history of 45+ miles.

Weekly Mileage

Most sub-1:20 half plans peak at 55-75 miles per week (88-120 km). Six days per week, sometimes with one double.

The Plan Structure

A typical sub-1:20 week in mid-build:

Monday: Easy 6-8 miles
Tuesday: VO2max session. 6×1 km at 5K pace, or 5×1 mile at 5K-10K pace. 10-12 miles total.
Wednesday: Easy 7-9 miles
Thursday: Threshold workout. 5×1 mile at half marathon pace, or 3×2 miles at half marathon pace. 11-13 miles.
Friday: Easy 5-7 miles or rest
Saturday: Easy 5 miles + 4×100m strides
Sunday: Long run 14-18 miles, with half-marathon pace miles in the back half

Total: 55-65 miles. Two hard quality days plus the long run with race-pace work.

Half-Marathon-Pace Workouts

Week 5: 13 miles with 6 at half marathon pace
Week 7: 14 miles with 8 at half marathon pace
Week 9: 2×5 miles at half marathon pace (key dress rehearsal)
Week 10: 3 × 4 km at half marathon pace
Week 11: 15 miles with 10 at half marathon pace

Pacing Sub-1:20

6:06 per mile pace has zero margin. First mile 6:10. Lock into 6:05-6:06 from mile 2 through mile 11. Final 2.1 miles, push if you can.

Common Mistakes

Too much volume, not enough threshold. Sub-1:20 is built on threshold, not on mileage alone. Two quality sessions per week is the minimum.

Going out at sub-1:15 pace. 5:45 for mile 1 destroys the second half.

Wrong course choice. Sub-1:20 needs a flat fast course. Pick wisely.

Build a sub-1:20 half plan

Pheidi creates a half marathon training plan calibrated to your exact goal time and current fitness. Free, adaptive.

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Key Takeaways

Sub-1:20 is 6:06 per mile for 13.1 miles. The semi-elite half marathon line.
Prerequisites: 17:30 5K, 36:30 10K, 2+ halves completed, 45+ mpw history.
Peak 55-75 mpw, two quality sessions, six days per week typical.
Key workout: 2×5 miles at half marathon pace, 3 weeks before race day.
Flat fast course required. Pacing discipline is non-negotiable.

Frequently Asked Questions

What pace is a 1:20 half marathon?

6:06 per mile, or 3:47 per kilometre, held for the full 13.1 miles (21.1 km). Even-pace checkpoints are 18:58 at 5 km, 37:55 at 10 km, 56:53 at 15 km, and 1:15:50 at 20 km. Those splits land you on 1:20:00 exactly, so to finish under it you want a few seconds in hand by halfway rather than a sprint at the end.

How fast do I need to be to attempt sub-1:20?

Recent 5K under 17:30 and a 10K under 36:30 are the honest prerequisites. The VDOT math: a 17:30 5K predicts ~1:19 half. Most sub-1:20 runners have 5K PRs in the 16:30-17:30 range.

How many miles a week for sub-1:20?

Most successful sub-1:20 plans peak at 55-75 mpw. Higher than the sub-1:30 step (40-55 mpw), with more frequent quality work. Six days per week is typical, sometimes with one double.

What's the key workout for sub-1:20?

2 × 5 miles at half marathon pace with 5-minute jog between, or 3 × 4 km at half marathon pace. The dress rehearsal that proves the fitness is there.

How long is the longest run?

14-18 miles. Race-pace volume inside the long run matters more than total distance: a 15-miler with 10 at half-marathon pace is more valuable than an 18-miler at easy pace.

Is sub-1:20 reachable without a marathon background?

Yes. Sub-1:20 is a pure speed/threshold goal more than a distance goal. Many sub-1:20 runners have never run a marathon. The training focus is 5K-to-10K speed plus sustained threshold volume.

What 1:20 training actually looks like

6:06Goal pace / mi
75 miPeak week
18 miLongest run
12Weeks
6Runs / week

That peak week is the honest cost of the goal. Running 1:20 for a half marathon means 6:06 per mile (3:47 per km) held the whole way, and the training that supports it tops out around 75 mi a week with a 18 mi long run. If those numbers don't fit your life right now, the goal isn't wrong, the timeline is.

Week 1, day by day

Week 1 is base phase, so there is no hard session in it. The strides are form work at the end of an easy run, not a workout. Distances are ranges for the same reason the ladder below uses ranges: the right number depends on what you're already running. The week totals 50 to 68 mi across 6 runs.

Week 1 of a 1:20 half marathon training plan, day by day
Day	Workout	Distance	Pace	Why
Monday	Easy run	6.5 to 10 mi	Easy pace	Conversational the whole way. If you could not talk, it was too fast.
Tuesday	Easy + strides	8 to 12.5 mi	Easy pace, strides relaxed	Strides after an easy run, 6 x 20 sec. Form work at the end of an easy run, not a workout.
Wednesday	Easy run	7.5 to 11 mi	Easy pace	Conversational the whole way. If you could not talk, it was too fast.
Thursday	Easy run	7.5 to 11 mi	Easy pace	Conversational the whole way. If you could not talk, it was too fast.
Friday	Rest	-	-	Full rest, or an easy walk or bike if you want to move.
Saturday	Long run	14 mi	Easy pace	The anchor of the week. Run it easy; the distance is the stimulus.
Sunday	Recovery run	6.5 to 9.5 mi	Easy pace or slower	The shortest, softest run of the week. Slower than easy is fine here.

Your training paces for 1:20

Jack Daniels' zones, worked back from the goal time (VDOT 58.4). Read these as what running 1:20 requires, not what you can run today. If easy pace looks slow, that's the table working: easy days being too fast is the most common training mistake at every level.

Training pace zones for a 1:20 half marathon
Zone	Per mile	Per km	What it's for
Half marathon goal pace	6:06	3:47	What 1:20 actually is, mile after mile.
Easy	7:16	4:31	Most of every week. Slower is fine; faster is the classic mistake.
Marathon	6:16	3:54	Steady and controlled. The pace a long-run finish settles into.
Threshold	6:02	3:45	Comfortably hard. Tempo runs and cruise intervals live here.
Interval	5:32	3:26	VO2max work. Repeats of 3 to 5 minutes with jog recoveries.

The same fitness that runs 1:20 for a half marathon is worth roughly 17:27 for 5K, 36:11 for 10K and 2:47:11 for marathon. Equivalents are a sanity check, not a promise: the longer the distance, the more the prediction assumes training you may not have done yet. Run the numbers on your own recent race with the VDOT calculator.

The week-by-week plan

12 weeks, 6 runs a week. The long run is the anchor and steps back every fourth week so the build doesn't just climb until something breaks. Weekly mileage is a range because the right number depends on what you're already running, which is exactly the part a static plan can't know about you.

Week-by-week training schedule
Week	Phase	Long run	Weekly	Key workout
1	Base	14 mi	50 to 68 mi	Strides after an easy run, 6 x 20 sec
2	Base	14.5 mi	50 to 68 mi	Strides after an easy run, 6 x 20 sec
3	Base	15.5 mi	52 to 70 mi	Strides after an easy run, 6 x 20 sec
4	Base	15 mi	51 to 69 mi	Strides after an easy run, 6 x 20 sec
5	Build	16 mi	52 to 71 mi	Tempo, 4 to 6 mi at half-marathon effort
6	Build	16.5 mi	53 to 72 mi	Tempo, 4 to 6 mi at half-marathon effort
7	Build	17.5 mi	54 to 74 mi	Tempo, 4 to 6 mi at half-marathon effort
8	Build	17 mi	54 to 73 mi	Tempo, 4 to 6 mi at half-marathon effort
9	Build	18 mi	55 to 75 mi	Tempo, 4 to 6 mi at half-marathon effort
10	Taper	13 mi	36 to 49 mi	Short goal-pace touch, 2 to 3 mi, then done
11	Taper	9 mi	25 to 34 mi	Short goal-pace touch, 2 to 3 mi, then done
12	Taper	Race day	Race week	Two or three short easy runs with a few strides. Nothing else.

Easy runs fill the rest of the week and should stay genuinely easy: conversational, slower than feels satisfying. That's the 80/20 split doing its work. If you miss a week, don't try to make it up. Rejoin the plan where the calendar is, not where you wish you were.