Compare calculators
Both calculators run independently β change the inputs on either side to compare results.
Running
Training Zone Calculator
Calculate your personalized heart rate training zones using the Karvonen or percentage-of-max-HR method. Use it when structuring your weekly runs to target specific fitness adaptations.
Fill in the required fields to see your result.
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.
Key differences
| Training Zone Calculator | Marathon Time Predictor | |
|---|---|---|
| Category | Running | Running |
| Inputs required | 4 | 2 |
| Result | Tempo Training Zone (bpm) | Predicted Marathon Time (minutes) |
| What it does | Calculate your personalized heart rate training zones using the Karvonen or percentage-of-max-HR method. Use it when structuring your weekly runs to target specific fitness adaptations. | 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. |