Enter your Mile time to see what it predicts for the half marathon.
Your mile time reflects your aerobic ceiling. This table shows what that ceiling predicts for the half marathon — 13.1 miles of sustained threshold-level effort. The physiological distance between a mile and a half marathon is significant; raw speed converts to half marathon fitness only with distance-specific training.
Quick answer: A 5:30 Mile runner (RPI 53.4) has equivalent Half Marathon fitness of 1:26:27 (6:36/mi). Range in this table: 4:00 Mile → 1:03:20 Half Marathon through 8:00 → 2:03:53.
| Mile Time | RPI | Half Marathon Equivalent | Equiv Pace |
|---|---|---|---|
| 4:00 | 76.5 | 1:03:20 | 4:50/mi(3:00/km) |
| 4:15 | 71.4 | 1:07:13 | 5:08/mi(3:11/km) |
| 4:30 | 66.9 | 1:11:07 | 5:25/mi(3:22/km) |
| 4:45 | 62.9 | 1:15:00 | 5:43/mi(3:33/km) |
| 5:00 | 59.4 | 1:18:49 | 6:01/mi(3:44/km) |
| 5:15 | 56.2 | 1:22:43 | 6:19/mi(3:56/km) |
| 5:30 | 53.4 | 1:26:27 | 6:36/mi(4:06/km) |
| 5:45 | 50.8 | 1:30:16 | 6:53/mi(4:17/km) |
| 6:00 | 48.4 | 1:34:08 | 7:11/mi(4:28/km) |
| 6:30 | 44.3 | 1:41:36 | 7:45/mi(4:49/km) |
| 7:00 | 40.7 | 1:49:16 | 8:20/mi(5:11/km) |
| 8:00 | 35.1 | 2:03:53 | 9:27/mi(5:52/km) |
Computed via StrideIQ’s RPI equation. Predictions assume distance-specific training is in place.
Mile → half marathon predictions have substantial divergence for runners who lack half marathon-specific training. The equivalency reflects aerobic potential, not fitness developed for sustained 90-minute effort. Runners who add threshold training and long runs (12–15 miles) typically close to within 5 minutes of their prediction.
This has the most divergence among the short-to-long predictions. The half marathon demands sustained threshold stamina for 70–120 minutes — a quality that mile training alone does not develop. Runners who add long runs and tempo work to their mile training typically land within 5–8 minutes of the equivalency.
A 5:00 mile (RPI 59.4) projects to 1:18:49 half marathon potential at 6:01/mi. Reaching this requires threshold-specific training and long runs to 12–15 miles.
Add weekly threshold tempo runs (20–35 minutes at threshold pace) and build long runs to 12–15 miles. These two additions develop the specific aerobic endurance and lactate stamina that convert raw mile speed into half marathon performance.