Performance lab
The tools
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Fueling & Hydration
Electrolytes, sodium, carbs, and what goes in the bottle.
Homemade Electrolyte Drink Calculator
Build a sweat-matched electrolyte drink for pennies, instead of paying $1.50 a stick.
Free: Per-bottle sodium, potassium, and magnesium recipe scaled to your sweat profile, with kitchen-scale teaspoon amounts and a cost-vs-LMNT breakdown.
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DIY Sports Drink Calculator
Build a dual-transporter maltodextrin + fructose race fuel for pennies. Exact gram recipe, osmolarity check, and gut-training plan.
Free: Per-bottle recipe with exact grams of maltodextrin, fructose, and sodium citrate scaled to your use case and gut status. Osmolarity check and cost vs commercial brands included.
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Sodium Calculator
Find your per-hour sweat sodium loss and replacement target by event, sweat profile, and climate, with a pre-race loading plan.
Free: Per-hour sodium and fluid targets scaled to your weight, sweat profile, and race climate, with a hyponatremia risk check, pre-race loading card, and hour-by-hour breakdown.
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Sweat Rate Calculator
Run a naked-weight sweat test to find your exact hourly fluid loss, then pipe it straight into your sodium and drink-mix plans.
Free: Your precise hourly sweat rate from a before-and-after weigh-in, plus percent body-mass lost, fluid deficit, and a recommended drinking rate. Feeds the sodium calculator directly.
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Hydration Calculator
Find your exact daily baseline and per-hour race-day fluid target from your body weight, sweat rate, and conditions. Urine color check and overdrinking warning included.
Free: Daily fluid baseline, per-hour exercise target, and a urine-color hydration audit scaled to your weight, activity duration, and climate.
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Carbs Per Hour Calculator
Dial in your in-race carbohydrate target in grams per hour, the glucose to fructose split, and an hour-by-hour feed plan for running or cycling.
Free: Your per-hour carb target from event duration, intensity, body weight, and gut training level, with a 2:1 glucose to fructose split, gels-per-hour, and an hour-by-hour fueling table.
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Race Preparation
Carb loading, caffeine, pre-workout, and pack lists.
Caffeine Calculator
Dial in your race-day caffeine dose and timing without the jitters or the crash.
Free: Pre-race dose (3-6 mg/kg) and peak-plasma timing window for your event and body weight.
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DIY Pre-Workout Calculator
Build a goal-matched endurance pre-workout from bulk ingredients. Exact doses, two-window timing, and a fraction of the cost of a commercial tub.
Free: Dose-by-dose formula scaled to your goal, event, and stim level, with a beetroot and citrulline blood-flow base, caffeine plus theanine, a timing plan, and cost vs a commercial pre-workout.
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Carb Loading Calculator
A no-bloat, hour-by-hour carb-loading countdown that saturates glycogen without the heavy legs and gut bombs.
Free: Your daily carb target (g/kg) and a low-residue, hour-by-hour loading timeline with gram-accurate food portions for the 36 hours before your race.
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Volume-Corrected Marathon Predictor
Predict your marathon from a recent race, corrected for weekly mileage so low-volume runners get a realistic time instead of an optimistic Riegel guess.
Free: Your marathon prediction from a recent 5K, 10K, or half, adjusted for weekly training mileage, with the uncorrected Riegel time for comparison and your target marathon pace.
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Race-Day Packing and Transition Matrix
A personalized, zone-by-zone gear checklist so you never forget the timing chip again.
Free: Itemized packing list by zone for your sport, distance, weather, and travel type.
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Training & Zones
Heart rate zones, FTP, and power for structured training.
FTP Calculator
Turn one FTP number into a complete cycling power-zone training structure.
Free: 7 Coggan power zones in watts and percentage from your FTP, plus FTP estimates from a 20-minute test or ramp test.
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Heart Rate Zone Calculator
Find all 5 training heart-rate zones, with your Zone 2 aerobic base front and center.
Free: All 5 heart-rate zones in bpm from your age and resting HR, with Zone 2 (the fat-burning aerobic base) called out. %HRmax and Karvonen methods.
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ACWR Calculator
Find your Acute:Chronic Workload Ratio and the exact weekly mileage ceiling that keeps you in the low-injury-risk sweet spot.
Free: Your ACWR from this week plus up to 4 prior weeks, the injury-risk zone (sweet spot, caution, or danger), and your safe weekly mileage ceiling. Enter 4 weeks of history for the most accurate chronic load.
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TSS and Taper Planner
Plan a day-by-day taper from your training load and see whether you will actually peak on race day, no TrainingPeaks subscription needed.
Free: A full Performance Management Chart and day-by-day taper: fitness (CTL), fatigue (ATL), and form (TSB) projected to race day, with a peak verdict. Connect Strava to auto-fill your load from the last 6 weeks.
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VDOT Calculator
Enter a recent race result to get your VDOT running fitness score and five personalised training zone paces, built on Jack Daniels' proven system.
Free: Your VDOT score and Easy, Marathon, Threshold, Interval, and Repetition zone pace ranges based on your recent race.
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Conditions & Physiology
Heat, altitude, and physiology adjustments for race day.
Female Athlete Cycle Calculator
Find which phase of your cycle race day falls in, then get phase-specific adjustments to temperature, sodium, fueling, and hydration strategy.
Free: Your race-day cycle phase with the Cycle-Phase Performance Protocol: core temperature offset, sodium target delta, carb fueling note, and hydration flag, cross-linked to your race-day tools.
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Altitude Performance Calculator
Find your oxygen-corrected power and pace before you blow up chasing sea-level numbers at Leadville or UTMB.
Free: Your exact FTP and threshold pace reduction at race elevation versus training elevation, with an acclimatization recovery timeline showing how each day at altitude closes the gap.
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Heat-Adjusted Pace Calculator
Stop panicking about summer paces. Convert your goal pace for real temperature and dew point so easy stays easy.
Free: Your heat-adjusted goal pace from temperature plus dew point, with the exact per-mile slowdown and an effort-cap note so you do not redline your easy runs.
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Heat Acclimation Planner
Build a day-by-day heat-acclimation protocol that times your plasma-volume gains to land exactly on race day.
Free: Your full 8-to-14-day protocol scaled to race climate, baseline fitness, and sweat profile, with per-session duration, intensity cues, and fluid plus sodium targets, expected adaptations, and a race-day pre-cooling card.
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Gear & Speed
Bike fit, aerodynamics, and equipment ROI.
Crank Length Calculator
Switching to shorter cranks? Get the exact saddle-height bump and gearing change so your fit and leverage stay dialed.
Free: The exact saddle-height offset and gearing/leverage change when you switch crank length, plus the hip-angle and aero upside of going shorter.
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Bike Tire Pressure Calculator
Dial in front and rear tire pressure for road, gravel, tri, and MTB from your weight, tire and rim width, casing, and surface.
Free: Berto 15% tire-drop front and rear pressure scaled to your weight, measured tire width, casing, surface, and weather, with a hookless safety cap and the watts cost of over-inflating.
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Cycling Speed Calculator
Find your speed at any wattage, then see exactly how many minutes aero wheels or losing weight saves you over your race distance.
Free: Ground speed at your power, weight, grade, and setup, plus an Aero-Weight Time-Cost Model ranking every upgrade by minutes saved over your race distance.
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Cycling Aero Calculator
See the watts and the minutes each aero upgrade actually buys you, for your position, speed, wind, and event, before you spend a cent.
Free: Watts saved and time saved for your position, wheels, helmet, skinsuit, and socks at your speed, wind, and yaw, with a per-component breakdown and a best-value pick.
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