Compare calculators
Both calculators run independently โ change the inputs on either side to compare results.
Running
Marathon Time Predictor
Predict your marathon finish time from a recent 5K, 10K, or half marathon result using empirical scaling factors tuned to typical recreational runners. Use it to set a realistic goal before your first marathon or to validate a training cycle.
Fill in the required fields to see your result.
Running
Running Race Equivalency Calculator
Predict your expected finish time at any race distance using a recent race result. Based on the Jack Daniels equivalency model, it adjusts for the extra fatigue cost of longer distances.
Fill in the required fields to see your result.
Key differences
| Marathon Time Predictor | Running Race Equivalency Calculator | |
|---|---|---|
| Category | Running | Running |
| Inputs required | 2 | 4 |
| Result | Predicted Marathon Time (minutes) | Predicted Race Time (minutes) |
| What it does | Predict your marathon finish time from a recent 5K, 10K, or half marathon result using empirical scaling factors tuned to typical recreational runners. Use it to set a realistic goal before your first marathon or to validate a training cycle. | Predict your expected finish time at any race distance using a recent race result. Based on the Jack Daniels equivalency model, it adjusts for the extra fatigue cost of longer distances. |