Race Training Plan Generator

Building one of these by hand means drawing a grid of weeks and then arguing with yourself about the numbers. People get it wrong in a predictable direction — too much, too soon — because a plan that adds a flat amount each week grows fastest in percentage terms right at the start. This builds the plan from rules instead, and then checks the plan that came out against every one of them.

Race

Weeks until the race

Up to 24. Each race has a sensible minimum.

Kilometres a week now

What you are comfortably running already.

Runs a week

Between 3 and 6.

Most a week may rise, per cent

Ten is the usual rule of thumb.

Most of a week the long run may be, per cent

Between 20 and 50.

12 weeks to a half marathon, peaking at 32.2km a week with a longest run of 11.3km. 280.1km in total.

Week	Mon	Tue	Wed	Thu	Fri	Sat	Sun	Total
1	—	4.3	4.3	—	4.3	—	7	20
2	—	4.8	4.8	—	4.8	—	7.7	22
3	—	5.2	5.2	—	5.2	—	8.5	24.2
4 ·easy	—	3.9	3.9	—	3.9	—	6.4	18.2
5	—	5.2	5.2	—	5.2	—	8.5	24.2
6	—	5.8	5.8	—	5.8	—	9.3	26.6
7	—	6.3	6.3	—	6.3	—	10.2	29.3
8 ·easy	—	4.8	4.8	—	4.8	—	7.7	22
9	—	6.3	6.3	—	6.3	—	10.2	29.3
10	—	7	7	—	7	—	11.3	32.2
11 ·taper	—	4.2	4.2	—	4.2	—	6.8	19.3
12 ·taper	—	2.8	2.8	—	2.8	—	4.5	12.9

Distances in kilometres. Sunday is the long run; the intervals and tempo days are the hard ones.

✓ No week goes further than the step above the peak so far — the largest rise over the highest week yet is 10 per cent, against your limit of 10
✓ There are easier weeks to absorb the work — 4 of 12 weeks are shorter than the week before, including the taper
✓ The build carries on after each easier week — the highest week of each stretch rises: 24.2km, 29.3km, 32.2km
✓ The long run stays a sensible share of the week — at most 35 per cent of a week, against your limit of 35
✓ The long run is the longest run of its week — in all 12 weeks Sunday's run is longer than every other
✓ No two hard days fall together — every hard session has an easy day or a rest day after it
✓ The taper only goes down — the last 2 weeks fall from the peak of 32.2km to 12.9km
✓ Each week's sessions add up to its total — 280.1km over 12 weeks

What this generator does

Grows the weekly distance from where you are now, drops every fourth week back (except the week before the taper) and then picks the build up where it left off, makes the long run the longest run of its week and holds it to a share of the week and to the race distance wherever a week of that many runs can stay inside both — where it cannot, every run of that week is the same length — lays the sessions out so no two hard days touch, and tapers the last two weeks.

How to use this tool

Pick the race and how many weeks you have.
Say how far you already run in a comfortable week, and how many days you can run.
Set how fast the plan may build and how much of a week the long run may take.
Read the grid, copy it, and adjust anything that does not suit you.

Understanding the controls

Race: 5 kilometres, 10 kilometres, a half marathon or a marathon. This sets the shortest plan that makes sense and how far the long run goes: the race itself up to 10 kilometres, four fifths of it beyond. A week too big for its runs to stay under that has every run the same length instead.
Weeks until the race: How long you have. A shorter plan starts from the same weekly distance and simply peaks lower, because the step is capped either way.
Kilometres a week now: What you are comfortably running already, which is where week one starts. Being honest here is the whole point.
Runs a week: Three to six. The layout of hard and easy days changes with it, and is arranged so no two hard days fall together.
Most a week may rise, per cent: The cap on how much further any week may go than the highest week so far. Ten per cent is the usual rule of thumb. With an easier week every fourth, two weeks in each four step up, so ten per cent a week comes to about a fifth more every four weeks.
Most of a week the long run may be, per cent: The long run is capped as a share of the week, so it grows with everything else rather than running away from it. It is never shorter than another run of its week, so a share under an equal one cannot be kept: under a third with three runs, under a quarter with four. Every run is then the same length, and the page says so.

Common use cases

A plan that starts from your current mileage instead of somebody else's
Fitting a build into however many weeks are actually left
Seeing what three, four, five or six running days a week looks like
Working out how much the long run should be at its longest
Understanding why a plan steps back every fourth week

How this generator works

The build grows by your step each week and drops to three quarters every fourth week. The week after an easier week goes back to the highest week so far — not a step up from the easier week, which at ten per cent would bring the plan round in a circle, since three rises of a tenth and a drop to three quarters come to a shade under where they started — and the build carries on from there. From 20 kilometres at ten per cent, sixteen weeks run 20, 22, 24.2, 18.2, 24.2, 26.6, 29.3, 22, 29.3, 32.2, 35.4, 26.6, 35.4, 39, then the taper. The last week before the taper is never the easier one: where the count of four would land on it — plans of 6, 10, 14, 18 and 22 weeks — that week builds instead, so the taper comes straight off the highest week and the plan does not fall for three weeks running. The taper takes the last two weeks down to sixty and forty per cent of the peak. Sunday's long run is the lesser of your share of the week and the race's limit, and the other runs split the rest evenly — unless that would leave them longer than it. A week of four runs has a longest run of at least a quarter of the week whatever anyone plans, so a 5 kilometre plan at 32 kilometres a week cannot keep its longest run to 5: there the four runs are 8 each, and the page counts those weeks and says why. Distances are kept at full precision throughout and rounded only where they are shown — rounding each session and adding them up moves a week's total by enough to break the very rules the plan is built on. Every rule is then checked against the finished plan: no week goes further than the step above the highest week so far, the weeks marked easier are the ones shorter than the week before, the build is back at its highest after each easier week and reaches higher in each stretch, the long run stays inside its share or, where an equal share of the week's runs is more than that, is no more than an equal share, no run of any week is longer than its long run, no two hard days fall together anywhere in the plan including across the Sunday-to-Monday boundary, each taper week is below the week before it and the taper starts from a building week, and each week's sessions add up to the total printed beside them.

Randomness and fairness

Nothing is random. The same settings always build exactly the same plan.

For how randomness is produced across the whole site, see how Generate Random works.

Limitations and good to know

These are widely used planning conventions, not coaching or medical advice, and no plan can know anything about your health or history.
Paces are described rather than prescribed; the pace calculator works those out from a recent race.
Cross-training, strength work and stretching are not scheduled here.
A plan that starts from a higher weekly distance than you really run is not made safe by any of these checks.

Privacy and your data

The plan is built in your browser from the numbers you type. No distances or settings are transmitted or stored.