A 5K or 10K in. Your half out.
Type your recent 5K or 10K time. We project your half marathon finish using the Riegel formula — the standard for short-to-medium distance prediction.
From 10K in 50:00, here are your projected race times.
Find Marathon races →Reference table — popular shorter-race times and the Riegel-projected half. Most accurate when input is within ~3× of half (i.e., 5K-10K predict half well).
| Resultado de entrada | Predición | Notas |
|---|---|---|
| 5K 22:00 | Half ~1:42 | Strong sub-1:45 target. |
| 10K 40:00 | Half ~1:29 | Sub-1:30 club. |
| 10K 45:00 | Half ~1:39 | Solid sub-1:40 base. |
| 10K 50:00 | Half ~1:50 | Approaching sub-1:50. |
| 10K 55:00 | Half ~2:01 | Sub-2-hour half goal. |