Running Calculator
Running Calculator for Race Times, Paces, and Training Zones
Whether you’re training for your first 5K, chasing a marathon PR, or fine-tuning your fitness for competitive racing, this running calculator gives you fast, accurate predictions using the Riegel formula. Enter any race distance and finishing time, and you’ll instantly see:
- Equivalent race performances across common distances
- Pace per mile and per kilometer
- Recommended training paces based on your running experience
- Heart rate zone estimates
- A suggested weekly training structure
- Tools for tuning your personal slowdown factor
- Saved setups for tracking progress over time
This tool was designed for runners of all levels, utilizing proven coaching methods and personalized performance modeling.
Get started using the Running Calculator below or learn more about how it works here.
How the Running Calculator Works
This calculator uses your past race performance and applies the Riegel prediction model, a well-validated method for estimating how pace slows as distance increases. That slowdown varies for each runner, so this tool lets you:
- Adjust your Distance Slowdown Factor (k)
- Set your experience level (Beginner, Intermediate, Advanced)
- Save race results to customize future predictions
It’s the closest thing to having a personal coach analyze your running data.
Training Paces Based on Your Goals
Runners train best when they use specific pace zones that target the right energy systems. This calculator automatically generates:
- Easy / Recovery Pace (E) — for building your aerobic base
- Marathon Pace (M) — steady aerobic running for endurance
- Threshold Pace (T) — comfortably hard “no-man’s-land” workouts
- Interval Pace (I) — higher-intensity speed development
- Repetition Pace (R) — quick, economy-focused running
You’ll also see pace per mile, pace per kilometer, and estimated heart-rate zones based on your max HR.
Race Pace Predictions for Popular Distances
Using your input race, this tool provides predicted finish times for:
- Marathon
- Half Marathon
- 15K
- 10K
- 5K
- 2 Mile
- 3200m
- 3K
- 1 Mile
- 1500m
These predictions help you set realistic goals, pace your workouts, and understand where your strengths lie.
Perfect for Training Plans, Goal Setting, and Progress Tracking
This calculator is designed for:
- New runners building up to longer races
- Experienced runners adjusting goal times
- Coaches creating race plans
- Athletes that are monitoring improvements across a season
- Anyone who wants accurate training paces personalized to their ability
You can also save setups so you can compare past results, see improvements, and recalibrate predictions over time.
Brought to You by Sunrise Running Company
As a runner-focused coaching brand, Sunrise Running Company helps athletes improve performance with:
- Personalized coaching
- Training plans
- Running resources
- Community support
This running calculator is part of our mission to provide reliable, accessible tools for runners everywhere.
Start Using the Running Calculator
Scroll up to enter your race time and explore your personalized race predictions and training paces. Make adjustments, save results, and use these insights to guide your running journey.