Running Calculators
Last updated: October 2026
Heart Rate Training Zones Calculator
Calculate your personalised heart rate training zones using the Karvonen heart rate reserve method, which factors in resting heart rate to give zones that actually reflect your cardiovascular fitness.
Marathon Training Calculator
Get an easy-run pace from your goal marathon time, or a peak weekly mileage target built up from your current mileage at about 10% a week, with cutback and taper weeks, capped at a typical plan peak for your experience level.
Training Pace Zones Calculator
Find your easy running pace and Jack Daniels-style training zones (easy, marathon, threshold, interval) from a recent 5K, 10K, half-marathon or marathon time.
Marathon Fueling Calculator
Calculate a carbohydrate target for a marathon or long race in grams per hour and in total, from your expected finish time, effort and weather, using the duration-based sports-nutrition guideline of 30, 60 or up to 90 g of carbs per hour.
Running Cadence Calculator
Estimates a reference running cadence (steps per minute) from your height, current pace and experience level, and shows how to work out your stride length from it.
Running Cadence Optimizer (Step-Rate Increase)
Plan a safe increase in running cadence: enter the steps per minute you take now and your pace, choose +5%, +7.5% or +10%, and get your target cadence and the shorter stride that goes with it at the same pace.
Altitude Pace Adjustment
Estimate how much slower your running pace will be at elevation compared to sea level.
Running Power-to-Weight Calculator (W/kg)
Calculate your running power-to-weight ratio (W/kg) from your critical power and body weight, with the percentage-of-critical-power zones used to structure interval and threshold sessions.
Running Recovery Time Calculator
Estimate how many days to allow before your next hard run, from the workout's length and intensity, your age and your training level.
Marathon Taper Calculator
Plan each week of your pre-race taper: mileage steps down exponentially from your peak week to a race-week volume of 40β60% of peak, the reduction supported by taper research, over a 2β4 week taper.
Running Heat Index Calculator
Estimate how much to slow your easy run pace on hot, humid days to keep the same effort.
Running Calorie Calculator
Calculate how many calories you burn on a run based on your weight, distance, pace, and terrain type.
Running Race Equivalency Calculator
Predict your expected finish time at any race distance from a recent race result, using Pete Riegel's endurance formula T2 = T1 Γ (D2/D1)^1.06, which adds the extra fatigue cost of longer distances.
Altitude Running Adjustment Calculator
Estimate how much slower your running pace will be at high altitude compared to sea level.
Pace Calculator
Calculate your running pace per kilometer and per mile, and your speed in km/h and mph, from distance and finish time, with projected 5K to marathon times at that pace.
Training Load Calculator
Quantify your overall training stress each week by combining mileage, intensity, hard workout count, and years of experience.