Shed

Free tool · Taper

Taper Calculator

Week-by-week volume for the run-in to your race, from your peak week. The technique is simple and counterintuitive: cut the mileage sharply and keep running fast.

Race

Three weeks suits higher mileage and anyone over 40. Two is enough off lower volume.

The rule

Cut the volume. Keep the intensity. A taper of easy jogging only leaves you flat on the start line, which is the most common way to get this wrong.

Your 3 week taper

  • 3 weeks out

    36 mi80%

    Last long run. Keep both quality sessions, shorten them. Long run about 10.

  • 2 weeks out

    27 mi60%

    One quality session with race-pace work. This is the week you feel worst. Long run about 8.

  • Race week

    18 mi40%

    One short sharp session early. Two easy days before.

Percentages are of your peak week. The long run figure is roughly 28 percent of that week’s volume, which is where it usually sits in a taper.

Stop calculating. Start training.

These numbers are the first 30 seconds of what Shed does.

Shed reads your Apple Health, grounds your VDOT in your actual training — not one race — and writes the whole block: every workout, every pace, adjusted as life happens. The calculator gives you a snapshot; Shed gives you the plan.

Get your plan on iPhone

Why a taper works

Training makes you fitter and more tired at once. Your performance on any day is roughly what your fitness allows minus what your fatigue takes away. Fitness is built slowly and fades slowly. Fatigue accumulates quickly and clears quickly.

A taper exploits that asymmetry. Cutting volume sharply for two to three weeks sheds most of the accumulated fatigue while costing very little fitness, and the gap between the two opens up. That gap is your race.

Keep the intensity

This is the part that gets reversed. Runners cut their hard sessions and keep jogging, which removes the stimulus that maintains sharpness and keeps the fatigue that comes from volume. It is exactly the wrong way round.

Every taper week should contain one short, sharp session at or near race pace. A few miles at goal pace, or six by 400 metres. Full intensity, a fraction of the usual volume. It costs almost nothing in recovery and it keeps your legs from forgetting what fast is.

Frequently asked

How long should I taper for a marathon?
Two to three weeks. Three suits higher-mileage runners and anyone over 40, whose recovery is slower. Two is often enough off lower volume, and it keeps you from feeling like you have stopped training.
Should I stop running before a race?
No. Complete rest for more than a day or two leaves most runners feeling flat and heavy. Keep running, much less of it, and keep some intensity in the sessions you do.
Why do I feel terrible during the taper?
It is close to universal. Legs feel dead, easy pace feels hard, and phantom niggles appear. Your body is repairing rather than coping, and the sensation of that is not the same as the sensation of being fit. It usually lifts two or three days before the race.
How much does a taper actually gain me?
The research consistently lands somewhere around two to three percent, which over a marathon is several minutes. It is one of the largest single-intervention gains available to a trained runner, which makes it a strange thing to improvise.
Can I taper too much?
Yes, though it is rarer than tapering too little. Beyond about three weeks of substantially reduced training you start losing fitness. Dropping intensity entirely is the more common version of the same mistake, and it costs more than the extra rest gains.

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