Race Time Predictor
Enter a recent race time and predict your finish for any distance. Uses three proven formulas so you know exactly what to aim for.
Beat Your Predicted Times with Motera
The best way to improve your race predictions is to run consistently. Motera turns every run into a strategy game where you capture real-world territory, compete on leaderboards, and earn XP. When running feels like a game, you actually want to get out the door and train.
Download Motera FreeFrequently Asked Questions
How accurate is the Riegel formula for predicting race times?
The Riegel formula is remarkably accurate for distances between 5K and marathon, especially for trained runners. It tends to be most accurate when predicting times for distances close to your input race. For example, predicting a half marathon from a 10K result is generally more reliable than predicting a marathon from a 5K. Most runners find predictions within 2 to 5 percent of their actual times when properly trained.
What is the difference between the Riegel and Cameron formulas?
The Riegel formula uses a simple power law relationship (T2 = T1 * (D2/D1)^1.06) and works well for most recreational runners. The Cameron formula uses a more complex fatigue curve that accounts for how fatigue increases at different rates for different distances. Cameron tends to give slightly faster predictions for shorter races and slightly slower ones for ultra distances.
Can I predict a marathon time from a 5K result?
Yes, but with caveats. The larger the gap between your input distance and predicted distance, the less accurate the prediction. A 5K tests your speed and VO2max, while a marathon tests endurance and fuel management. Someone who is fast at 5K but has not done long run training may find their actual marathon time is slower than predicted. For best results, use a 10K or half marathon time to predict a marathon.
Why do the three formulas give different predictions?
Each formula models the relationship between distance and fatigue differently. The original Riegel uses an exponent of 1.06, the adjusted version uses 1.07 (slightly more conservative for longer distances), and Cameron uses a curve-based approach. The range between them gives you a realistic window of what to expect on race day.
Should I use my training pace or race pace for predictions?
Always use your best recent race time or a genuine all-out time trial effort. Training paces are typically 30 to 60 seconds per mile slower than race pace. Using a training pace will give you predictions that are too slow. If you have not raced recently, do a solo time trial at a local track or measured course and give maximum effort.
How recent should my input race time be?
Ideally within the last 3 months. Fitness changes over time, so an old PR may not reflect your current ability. If you have been training consistently and improving, your current fitness may actually be better than your most recent race suggests. If you have taken time off, your predictions may be optimistic.
What does the performance level rating mean?
The performance level gives you context for how your time compares to other runners. Elite means you are in the top 1 to 2 percent of all runners. Advanced puts you in the top 10 to 15 percent. Intermediate is the middle of the pack, and Beginner means you are in the early stages of your running journey. Every level is an achievement and a starting point for improvement.
Do these formulas work for ultramarathons?
The formulas become less reliable beyond marathon distance because ultra running introduces variables like elevation, terrain, sleep deprivation, and nutrition strategy that shorter races do not have. The 50K prediction shown here should be treated as a rough estimate. For distances beyond 50K, specialized ultra prediction models that account for elevation and aid station stops are more appropriate.
How can I improve my predicted times?
The fastest way to improve race predictions is to actually train for your target distance. Include a mix of easy runs, tempo runs, intervals, and long runs in your training. Consistency matters more than intensity. Most recreational runners see significant improvements in their first 1 to 2 years of structured training, with 5K times dropping by several minutes and marathon potential improving dramatically.
How It Works
Enter a recent race time
Pick a distance you have raced recently and enter your finish time. The more recent and accurate, the better your predictions will be.
Three formulas crunch the numbers
The Riegel, adjusted Riegel, and Cameron formulas each calculate your predicted finish time using different mathematical models of running fatigue.
Get predictions for every distance
See your predicted finish times for 1 mile through 50K, with pace per kilometer and per mile. The range between formulas gives you a realistic target window.
Tips for Accurate Predictions
Use a recent race for best accuracy
A race from the last 3 months gives the most reliable predictions. Old PRs may not reflect your current fitness. If you have not raced recently, do a timed effort at a local parkrun or track.
Predict up, not just down
Most runners use this to predict marathon times from shorter races. But it works both ways. If you have a marathon result, you can see what your 5K potential is and train specifically for that distance.
Train for the distance you want to race
Predictions assume you are properly trained for the target distance. A runner with a fast 5K but no long runs will likely run slower than their predicted marathon time. The formulas work best when your training matches your goal.
Use the range as your target window
The three formulas give slightly different results. Use the fastest as your A goal, the average as your B goal, and the slowest as your safe starting pace. This helps you race smart without going out too fast.
