Free Running Tools
Race TimePredictor
Calculate your predicted race times for 5K, 10K, Half Marathon, and Marathon based on your recent performance.
Uses the Riegel formula with training adjustments
Calculate your predicted race times for 5K, 10K, Half Marathon, and Marathon based on your recent performance.
Enter your race details to calculate prediction
Select your preferred distance unit (miles or kilometers) that you'll use throughout the form.
Enter the details of your most recent race: the distance you ran, your finish time (in HH:MM:SS format), and the date of the race.
Input your target race distance - this is the distance for which you want to predict your time.
Add your current weekly training distance to help us factor in your fitness level.
Click "Calculate Prediction" to see your estimated finish time, pace, and confidence level based on your inputs.
Note: For the most accurate predictions, use a recent race time (within the last 12 weeks) and ensure your weekly training distance is up to date.
Get accurate race time predictions based on your recent running performance. Our calculator uses proven formulas and adjusts for training volume to give you realistic targets.