3K to Marathon Conversion Calculator
Your 3K time is a strong predictor of Marathon performance. This calculator converts your track fitness to a road racing target by factoring in the increased endurance, pacing discipline, and aerobic at 75-85% VO2max required at Marathon distance.
Quick answer: a 10:40 3000m converts to about 3:19:10 for the marathon (typical range 3:03:38 to 3:42:16).
3000m to Marathon conversion table
Estimates only – individual results vary with training, conditions and event experience.
| 3000m time | Predicted Marathon | Range |
|---|---|---|
| 8:20 | 2:35:36 | 2:23:28–2:53:39 |
| 8:35 | 2:40:16 | 2:27:46–2:58:52 |
| 8:50 | 2:44:56 | 2:32:05–3:04:04 |
| 9:05 | 2:49:36 | 2:36:23–3:09:17 |
| 9:20 | 2:54:16 | 2:40:41–3:14:29 |
| 9:35 | 2:58:56 | 2:44:59–3:19:42 |
| 9:50 | 3:03:36 | 2:49:18–3:24:54 |
| 10:05 | 3:08:16 | 2:53:36–3:30:07 |
| 10:20 | 3:12:56 | 2:57:54–3:35:20 |
| 10:35 | 3:17:36 | 3:02:12–3:40:32 |
| 10:50 | 3:22:16 | 3:06:31–3:45:45 |
| 11:05 | 3:26:57 | 3:10:49–3:50:57 |
| 11:20 | 3:31:37 | 3:15:07–3:56:10 |
| 11:35 | 3:36:17 | 3:19:25–4:01:22 |
| 11:50 | 3:40:57 | 3:23:44–4:06:35 |
| 12:05 | 3:45:37 | 3:28:02–4:11:48 |
| 12:20 | 3:50:17 | 3:32:20–4:17:00 |
| 12:35 | 3:54:57 | 3:36:38–4:22:13 |
| 12:50 | 3:59:37 | 3:40:57–4:27:25 |
| 13:05 | 4:04:17 | 3:45:15–4:32:38 |
| 13:20 | 4:08:57 | 3:49:33–4:37:50 |
| 13:35 | 4:13:37 | 3:53:51–4:43:03 |
| 13:50 | 4:18:17 | 3:58:10–4:48:16 |
| 14:05 | 4:22:57 | 4:02:28–4:53:28 |
How it works
The 3K→Marathon conversion blends Riegel's power-law scaling with VDOT oxygen-cost validation. With a 14x distance jump, the predictor applies additional correction factors for the major physiological shift between these events. Where both distances fall within aerobic range, critical speed modeling adds a third reference point. The result is a predicted time with a confidence range.
Training advice
Use a recent race or time-trial 3K for the best prediction. To reach your Marathon target, build high mileage and fueling strategy progressively. Marathon demands specific preparation — your 3K fitness provides the foundation, but high mileage and fueling strategy closes the gap.
Frequently asked questions
How accurate is a 3K to Marathon prediction?
With a recent all-out 3K time, predictions are typically within 4-8% of actual Marathon performance. Accuracy improves when the 3K effort is from the past 6-8 weeks under normal conditions.
What training should I do to reach my predicted Marathon time?
Focus on high mileage and fueling strategy. Your 3K fitness provides the speed foundation — building aerobic at 75-85% VO2max capacity through progressive training is the key to hitting the target.
Can I use an old 3K time for this prediction?
Recent times (within 6-8 weeks) give the most reliable predictions. Older results may not reflect your current fitness, especially if your training has changed significantly.