Marathon Taper Calculator
Calculates the recommended weekly training volume for each week of your pre-race taper, scaling down from peak mileage based on your recovery rate, taper length, and race distance. Ideal for marathon and ultramarathon preparation.
Last updated: September 2026
Formula below · 1 source (Wikipedia) · Updated Sep 2026
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About this calculator
Tapering is the structured reduction of training load in the weeks before a race to allow muscles, connective tissue, and the central nervous system to recover while retaining fitness. The formula used here is: final-week volume = peakWeeklyMiles × recoveryRate^weeksToTaper × raceDistanceFactor. Peak weekly mileage is your highest consistent training week before taper begins. The recoveryRate (0.85 slow, 0.75 average, 0.65 fast) is raised to the power of weeksToTaper to produce an exponential decay - each taper week keeps that fraction of the previous week's volume, mirroring how coaches step mileage down by 15-35% per week. The race distance factor (1.0 half marathon, 1.2 marathon, 1.4 ultra) keeps somewhat more volume for longer races, whose fitness depends more on sustained aerobic work. The result is the target volume in miles for the last week before the race; research on tapering (Bosquet et al., 2007) supports a total volume reduction of about 40-60% while keeping intensity.
How to use
Say your peak weekly mileage is 50 miles, your recovery rate is average (0.75), and you are running a marathon (factor 1.2). 2-week taper: 50 × 0.75² × 1.2 = 50 × 0.5625 × 1.2 = 33.8 miles. 3-week taper: 50 × 0.75³ × 1.2 = 50 × 0.422 × 1.2 = 25.3 miles. 4-week taper: 50 × 0.75⁴ × 1.2 = 50 × 0.316 × 1.2 = 19.0 miles. With a 3-week taper the final week is about 51% of peak, inside the recommended 40-60% window; keep a few short race-pace segments so your legs stay sharp.
Frequently asked questions
How many weeks should I taper before a marathon?
Most coaches recommend a taper of 2–3 weeks for a marathon, with 3 weeks being the most common prescription for high-mileage runners (above 60 miles per week) and 2 weeks suitable for lower-mileage trainees. The exponential decay built into this calculator means a 3-week taper with a 0.75 recovery rate drops you to about 42% of peak volume by the final taper week (about 51% after the marathon distance factor of 1.2) — a clinically meaningful reduction that allows glycogen supercompensation and soft-tissue repair. Tapering too aggressively (recovery rate below 0.6) can leave you feeling flat and undertrained on race day, while too little reduction risks arriving fatigued.
What recovery rate should I use in a marathon taper calculator?
A recovery rate of 0.70–0.80 is typical, corresponding to a weekly mileage reduction of 20–30% per step, which aligns with the most widely cited coaching guidelines. Beginners and injury-prone runners often benefit from a more aggressive taper (0.65–0.70), while experienced high-mileage runners may use 0.80 to avoid losing their aerobic edge. The right value also depends on how many taper weeks you have: a 2-week taper at 0.70 and a 3-week taper at 0.80 can produce similar total taper loads, so adjust both parameters together.
How does race distance affect taper volume in this calculator?
The race distance factor (1.0 half marathon, 1.2 marathon, 1.4 ultra) scales the final-week volume. For a half-marathon (21.1 km), the multiplier is approximately 0.50, halving the taper volume — appropriate because shorter races require less recovery stress. For an ultramarathon the factor rises to 1.4, reflecting the greater cumulative fatigue of ultra-distance racing and the need to arrive with well-stocked glycogen and repaired muscles. This scaling ensures the calculator remains useful across a range of race types without needing separate formulas.