Calculator methodology
Every calculator should make its method visible. Here you can separate exact arithmetic from physiological models and declared planning scenarios. Published equations are credited; heuristic coefficients are not presented as personal predictions. Qualification rules carry a race edition and source. A result supports a training decision only when its assumptions fit the athlete and the task.
Which results are arithmetic, models or scenarios?
Unit conversions, elapsed pace and additive splits are arithmetic. Race equivalence and slope energy cost are published models with limits. Heat, altitude, elevation-gain and wind corrections are declared sensitivity heuristics; their coefficients are not represented as validated personal predictions.
CORE Fitness Score
Score = (−4.6 + 0.182258v + 0.000104v²) / [0.8 + 0.1894393e^(−0.012778t) + 0.2989558e^(−0.1932605t)], where velocity v is m/min and t is minutes. Daniels–Gilbert equations. Pace bands are stated intensity scenarios.
Marathon pace calculator
Seconds per meter = finish seconds ÷ distance in meters.
Race time predictor
T₂ = T₁ × (D₂/D₁)^k. Riegel power law; k is adjustable, default 1.06.
Grade-adjusted pace calculator
Cr(g) = 155.4g⁵ − 30.4g⁴ − 43.3g³ + 46.3g² + 19.5g + 3.6. Flat equivalent pace = actual pace × Cr(0)/Cr(g).
Heat-adjusted pace calculator
Scenario penalty = 0.0035 × max(0, temperature °C − 12) + 0.0015 × max(0, dew point °C − 16) + 0.000012 × max(0, altitude m − 600). Range uses 0.5–1.5 times the penalty. Heuristic, not a fitted research equation.
Dew point calculator for runners
Magnus approximation: γ = ln(RH/100) + 17.625T/(243.04+T); dew point = 243.04γ/(17.625−γ), temperature in °C.
Altitude pace calculator
Declared altitude penalty: 0.000012 × meters above 600m, plus separately stated weather terms. Sensitivity band is 0.5–1.5 times the penalty; not a validated individual prediction.
Treadmill speed and pace calculator
Pace seconds/km = 3600 ÷ speed km/h. 1 mile = 1.609344 km.
Boston qualifier calculator
Official 2027 B.A.A. standard − chip time − applicable downhill index. Cutoff reference = standard − 317 seconds. Future cutoffs are not known.
NYC marathon qualifier calculator
Published NYRR time standard by age/division/distance minus entered chip time. Entry rules are separate from the arithmetic.
Swim CSS calculator
CSS seconds per 100m = (400m test seconds − 200m test seconds) / 2.
FTP and cycling zone calculator
20-minute estimate = test average watts × 0.95. Coggan zone boundaries are percentages of FTP.
Heart-rate reserve zone calculator
Target heart rate = resting HR + fraction × (maximum HR − resting HR). Five bands: 50–60, 60–70, 70–80, 80–90 and 90–100% reserve.
Sweat-rate calculator
Sweat L/hour ≈ (pre kg − post kg + consumed L − urine L) / duration hours.
Carbohydrate-loading calculator
Reference: 10–12 grams of carbohydrate per kilogram per day for 36–48 hours before prolonged endurance competition.
Race-day fueling planner
Total carbohydrate = duration hours × grams/hour. Equivalent gels = total grams ÷ product grams. Not a sodium or fluid prescription.
70.3 and IRONMAN split planner
Swim distance/pace + bike distance/speed + run distance/pace + T1 + T2. 70.3: 1.9/90/21.0975 km. Full: 3.8/180/42.195 km.
Saddle-height starting measurement
Starting saddle height in centimeters = inseam centimeters × 0.883. LeMond heuristic, not an individualized diagnosis.
Training load and CTL scenario
Load = hours × intensity factor² × 100. CTL next = CTL + (daily load − CTL)/42. TSS®/IF® are TrainingPeaks/Peaksware references.
Taper-volume scenario planner
Reference scenario: reduce volume by 40–60%, while individual frequency and intensity decisions remain separate.
Cycling watts per kilogram calculator
W/kg = watts ÷ body mass in kilograms. Pounds convert with 1 lb = 0.45359237 kg.
Printable race pace band
Cumulative split = total seconds × marker distance / race distance.
Running metabolic-power estimator
Metabolic watts ≈ Minetti running cost in J/kg/m × kg × m/sec. This is not a wearable power algorithm.
Hansons marathon pace reference
Marathon pace = goal seconds / 42,195 meters. No claim that this reproduces a licensed Hansons plan.
Body mass and running-cost calculator
Flat running cost = 3.6 J/kg/m × mass in kg. Kilocalories per km = 3.6 × mass × 1000 ÷ 4184. No pace-change equation is applied.
Why CORE Fitness Score?
The Daniels–Gilbert performance equations connect race speed, duration and estimated oxygen cost. The branded score is not a laboratory VO₂max measurement. Training bands use stated intensity fractions. Repetition pace is an oxygen-cost approximation, not an exact reproduction of a licensed pace table.
How are qualification rules maintained?
Rules carry an edition and source. Boston and NYC calculations currently use the published 2027 standards. Future entry cutoffs are unknown. Check the official organizer before making a registration decision.