Riegel Race Time Predictor (T₂ = T₁ × (D₂/D₁)^1.06) & Equivalent Pace Calculator

Predict 5K, 10K, Half Marathon, or Marathon finish times via T₂ = T₁ × (D₂/D₁)^1.06.

Predicted Target Race Finish Time
204.71 minutes
Target Race Pace (min / km) 4.85 min/km
Target Race Pace (min / mile) 7.81 min/mi
Average Running Speed 12.37 km/h
Inputs
⚡ Scenarios:
km
Distance of your recent benchmark race in kilometers (e.g., 5, 10, 21.0975).
min
Finish time of your recent benchmark race in minutes.
km
Target race distance in kilometers (42.195 km = Marathon, 21.0975 km = Half).
exponent
Riegel endurance fatigue factor (1.06 standard; 1.04 endurance monster, 1.08 speed runner).
Results & Graph
Predicted Target Race Finish Time
204.71 minutes
Target Race Pace (min / km)
4.85 min/km
Target Race Pace (min / mile)
7.81 min/mi
Average Running Speed
12.37 km/h

Predicted Target Race Finish Time

Graph 1 • Riegel Race Time Predictor • Domain Architecture & Live Telemetry Maps Known Race Distance Km, Known Race Time Minutes, Target Race Distance Km through Riegel Race Time Predictor Formula.
Riegel Race Time Predictor • Clinical & Physiological Reference Scale Low / Baseline Target / Reference Elevated / Watch High / Action Predicted Target Race Finish Time: 204.71 minutes Target Race Pace (min / km 4.85 min/km Target Race Pace (min / mi 7.81 min/mi Average Running Speed 12.37 km/h
Graph 2 • Predicted Target Race Finish Time Across Known Race Distance Km Sweep (40% → 160%) Evaluates PredictedTime_T₂ = KnownTime_T₁ × (TargetDistance_D₂ / KnownDistance_D₁) across 7 operating points (current input highlighted).
0 minute 297.4 minute 594.8 minute 540.7 4km 351.8 6km 259.3 8km 204.7 10km 168.7 12km 143.3 14km 124.4 16km
Graph 3 • Joint Sensitivity: Known Race Distance Km × Known Race Time Minutes Compares Predicted Target Race Finish Time when Known Race Time Minutes is shifted +25% (solid) vs. −25% (dashed).
0 minute 205.4 minute 410.8 minute --- Known Race Time Minutes @ 75% 373.5 -30% 304.0 -15% 255.9 +0% 220.7 +15% 193.8 +30%
Summary: Scaling 44.5 min over 10 km to 42.195 km (exponent 1.06) predicts a finish time of 204.71 minutes (3h 24.7m) at 4.85 min/km (7.81 min/mi).
Summary: Scaling 44.5 min over 10 km to 42.195 km (exponent 1.06) predicts a finish time of 204.71 minutes (3h 24.7m) at 4.85 min/km (7.81 min/mi).
⚡ Send result to: BMI →Calorie & TDEE →Pace, 1RM & HR Zones →
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Formula & Mathematical Methodology: Riegel Race Time Predictor Formula

PredictedTimeT₂ = KnownTimeT₁ × (TargetDistanceD₂ / KnownDistanceD₁)FatigueExponent
PredictedTime_T₂ = KnownTime_T₁ × (TargetDistance_D₂ / KnownDistance_D₁)^FatigueExponent
  • knownRaceDistanceKm: Known Race Distance Km (km)
  • knownRaceTimeMinutes: Known Race Time Minutes (min)
  • targetRaceDistanceKm: Target Race Distance Km (km)
  • riegelFatigueExponent: Riegel Fatigue Exponent (exponent)

Rounding: Clinical scores round to statutory integer or decimal precision; physiological metrics round to 2 decimal places.

Worked Example: Clinical / Physiology Scenario: Riegel Race Time Predictor

Predict 5K, 10K, Half Marathon, or Marathon finish times via T₂ = T₁ × (D₂/D₁)^1.06.

  1. Enter lab values, anthropometric measurements, or performance test metrics.
  2. Evaluate the reference equation: PredictedTime_T₂ = KnownTime_T₁ × (TargetDistance_D₂ / KnownDistance_D₁)^FatigueExponent.
  3. Inspect the primary classification, supporting indices, and 3 SVG charts.
Result: Computes Riegel Race Time Predictor via PredictedTime_T₂ = KnownTime_T₁ × (TargetDistance_D₂ / KnownDistance_D₁)^FatigueExponent.

Frequently Asked Questions

How does the Riegel Race Time Predictor (T₂ = T₁ × (D₂/D₁)^1.06) & Equivalent Pace Calculator compute its result?

It evaluates PredictedTime_T₂ = KnownTime_T₁ × (TargetDistance_D₂ / KnownDistance_D₁)^FatigueExponent directly in your browser and updates three custom SVG visualizations in real time.

Can I use Goal Seek to solve backwards for a target lab value or pace?

Yes. Click "🎯 Goal Seek" in the results toolbar to solve backwards for any numeric input parameter.

Are my health and biometric inputs kept private?

Yes. All calculations run 100% locally on your device with zero external transmission.

Health & Fitness · Endurance & Exercise Physiology

Riegel Race Time Predictor (T₂ = T₁ × (D₂/D₁)^1.06) & Equivalent Pace Calculator: inputs, method, and how to read the result

Predict 5K, 10K, Half Marathon, or Marathon finish times via T₂ = T₁ × (D₂/D₁)^1.06.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Known Race Distance Km: Distance of your recent benchmark race in kilometers (e.g., 5, 10, 21.0975).
  • Known Race Time Minutes: Finish time of your recent benchmark race in minutes.
  • Target Race Distance Km: Target race distance in kilometers (42.195 km = Marathon, 21.0975 km = Half).
  • Riegel Fatigue Exponent: Riegel endurance fatigue factor (1.06 standard; 1.04 endurance monster, 1.08 speed runner).

What the calculation includes

With the default values shown, Predicted Target Race Finish Time is 204.71 minutes. The calculation follows Riegel Race Time Predictor Formula; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Known Race Distance Km from 10 km to 11 km changes Predicted Target Race Finish Time from 204.71 minutes to 185.04 minutes. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses peer-reviewed clinical and sports physiology formulas.
  • For educational and informational reference only; clinical scores do not replace physician judgment or laboratory reference ranges.

Scope: Global Clinical & Sports Science Consensus Check the assumptions and limitations against your situation before relying on the estimate.

More in Health & Fitness: BMI Calculator (Body Mass Index), Calorie Needs & TDEE Calculator, Running Pace, One-Rep Max (1RM), Target Heart Rate & Calories Burned Calculator.