Running calculator
Race taper calculator
Plan the last weeks before a race: put in your peak weekly volume, choose how long the taper runs and how much volume comes off by race day, and get the week-by-week table — target volume, percentage of peak, long run and how much hard work to keep. Add a race date and every week gets its calendar dates. Free, instant, no sign-up.
The biggest week of your build-up — the one the taper is measured against, not your average week.
How far below your peak week race week lands. The pooled trials cluster around 40–60%; 50% is the middle of that band, not a rule.
How long is the taper?
One week for a 5 km or a mid-season race, two for a half, two to three for a marathon. Race week always counts as one of them.
Shape of the reduction
All three arrive at the same race week — they differ only in how they get there. Switch between them and watch the last row stay put.
Take the same slice off every week until race week.
Leave it blank and the plan still works — it is built from the weeks remaining. Fill it in and every row picks up its dates.
Your taper
Intensity does not appear in this table as a number because it is not meant to change. The volume column falls by 50% and the hard-session column barely moves — that is the whole idea, and it is the part people get wrong when they taper by taking the quality out instead of the mileage.
Volumes are rounded to one decimal and the percentages are worked out from the rounded figures, so every row agrees with itself. Long runs and hard-session counts are conventional coaching shapes rather than findings from the tapering trials — treat them as a starting point and keep whatever pattern your build-up already ran on.
The table gives you the volume — the coach turns it into the actual sessions, day by day.
What is a taper?
A taper is the planned reduction in training that sits between the end of a build-up and the start line. The problem it solves is that fitness and freshness are not the same thing: the training that made you fit also left you carrying accumulated fatigue, and on race day the fatigue is worth more to shed than the last few sessions are worth to keep. Cutting volume lets the fatigue clear while the fitness — which decays far more slowly — stays where it is. Done properly you arrive at the line no fitter than you were three weeks earlier, but able to use what you have.
How this calculator works
You give it one number that matters — your peak weekly volume — and three decisions: how many weeks the taper runs, how far below peak race week lands, and the shape of the curve in between. Every week's target is a fraction of the peak week, so the units never matter; kilometres in gives kilometres out. The three curves are normalised to arrive at the same race week, which means the shape only changes how the reduction is distributed, never where it ends up. The long run and hard-session columns come from conventional practice rather than from the trial data, and are there because a volume figure on its own does not tell you what to cut.
What the research actually says
The standard reference is the meta-analysis by Bosquet and colleagues (2007), which pooled 27 studies of tapering in trained endurance athletes. The pattern that came out of it was a reduction in training volume in the region of 40–60%, held for roughly two weeks, with training intensity unchanged and session frequency reduced only slightly — and even that combination produced an average performance gain of only about two to three percent. Two to three percent is several minutes over a marathon, so it is worth having, but it is a range and not a formula: the studies that make it up used tapers from one to four weeks and cuts across a wide band, and the differences between the curve shapes were small next to the difference between tapering and not tapering. Use the defaults here as a starting point, not as the number.
Using the plan
Pick the taper length from the race rather than from habit — a marathon earns two to three weeks, a 10 km rarely needs more than one. Then hold the line on two things. First, do not cut intensity: if you were running mile repeats at 10 km pace, keep running them at 10 km pace and just run fewer of them. Second, do not cut frequency much either; dropping from six runs a week to three does more harm than the extra rest does good, which is why the trials that reduced frequency heavily did worse than the ones that left it alone. Expect to feel sluggish somewhere in the middle of the taper and slightly restless by race week — both are normal, and neither is a reason to add a session back.