Marathon predictor
Enter your most recent race and basic endurance signals. If you’re keep it simple: choose your half marathon and use honest weekly km.
Use your recent 4–6 week average.
If you haven’t done a long run yet, be conservative.
Experience shifts the range slightly safer/less safe.
Tough conditions widen the range and push conservative.
Tip: If your inputs are optimistic (week km exaggerated or no long run), the “aggressive” number will mislead. When in doubt, choose the conservative end and aim to negative split.
What to do with your result
Use the range to pick a realistic goal, then build execution checkpoints.
Avoid the classic mistake: “banking time” early. Read: The math of time in the bank.
How to use this predictor (best practice)
- Start with your longest recent race (half marathon > 10K > 5K).
- Be honest with weekly km. Overstating volume makes predictions dangerously aggressive.
- Use a range, then pick a target you can execute in your conditions.
- Generate checkpoints + pace band in the Marathon Pace Calculator.
- Plan execution with splits and negative split pacing.
Recommended reading:
Choose a realistic marathon goal time · Why starting too fast costs minutes · Pacing in heat/wind/hills
Marathon predictor FAQ
Is this marathon time predictor accurate?
It’s an estimate. It blends your race performance with endurance signals (weekly distance + longest run) to produce a realistic range. Your actual result depends heavily on fueling, pacing, conditions, and marathon-specific training.
Why does it show a range instead of one time?
Because marathon outcomes vary. Two runners with identical 10K times can differ massively at 35K depending on durability and execution. A range is safer and more useful.
What race distance predicts marathon best?
A half marathon usually predicts marathon better than a 10K or 5K because it captures more endurance. If you only have a 5K, use the conservative end of the range.