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Calcimator

Race Predictor Calculator

Predict race finish times across distances using the Riegel formula. Enter a known race result to estimate times for 5K, 10K, half marathon, marathon, and ultra distances.

Inputs

mi

Results

Known Race Pace

8:03

1 Mile Time7:13
5K Time23:59
10K Time50:00
Half Marathon Time1:50:19
Marathon Time3:50:01
50K Time4:35:21
5K Pace7:43
Half Marathon Pace8:25
Marathon Pace8:46
How to Use This Calculator
  1. Enter your Known Race Distance in kilometers (e.g., 5 for a 5K, 10 for a 10K, 21.1 for a half marathon, 42.2 for a marathon).
  2. Enter your actual finish time for that race in Hours, Minutes, and Seconds.
  3. Review predicted finish times for 1 Mile, 5K, 10K, Half Marathon, Marathon, and 50K.
  4. Check the Known Race Pace along with the 5K, Half Marathon, and Marathon paces per mile.
  5. Use predictions to set realistic goal times before registering for a new race.

What each input means

Known Race Distance
The distance of the race you've already completed, in kilometers. Common values: 5 (5K), 10 (10K), 21.1 (half marathon), 42.2 (marathon).
Finish Time Hours
Hours portion of your finish time for the known race.
Finish Time Minutes
Minutes portion of your finish time.
Finish Time Seconds
Seconds portion of your finish time.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Known Race Distance = 10, Finish Time Hours = 0, Finish Time Minutes = 50, Finish Time Seconds = 0 = 4 input(s) provided
  2. Calculate Known Race Pace
    8:03 = 8:03

Engine last updated . Checked against 1 independently-derived test — how we verify calculators.

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