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.
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: Volume = peakWeeklyMiles × recoveryRate^weeksToTaper × (raceDistance / 42.195). Peak weekly mileage is your highest consistent training week before taper begins. The recoveryRate (a value between 0 and 1, e.g. 0.75) is raised to the power of weeksToTaper to produce an exponential decay — each successive taper week retains that fraction of the previous week's volume, mirroring how coaches traditionally step mileage down by 20–30% per week. The term raceDistance / 42.195 scales output proportionally for races shorter or longer than the standard marathon distance (42.195 km). The result is the target volume in miles for a given week of the taper.
How to use
Say your peak weekly mileage is 50 miles, you have a 3-week taper, your recovery rate is 0.75, and you are running a full marathon (42.195 km). Week 3 out (weeksToTaper = 3): 50 × 0.75³ × (42.195/42.195) = 50 × 0.422 × 1 = 21.1 miles. Week 2 out (weeksToTaper = 2): 50 × 0.75² × 1 = 50 × 0.5625 = 28.1 miles. Week 1 out (weeksToTaper = 1): 50 × 0.75¹ × 1 = 37.5 miles. Race week itself uses weeksToTaper = 0, giving 50 × 1 × 1 = 50 — so race week volume is capped at peak, and you would manually set it to a short shakeout run.
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 first taper week — 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 raceDistance / 42.195 multiplier scales the calculated volume proportionally to the standard marathon. 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 a 50-mile ultramarathon (roughly 80 km), the multiplier rises to about 1.90, 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.