Race Equivalent Times

Equivalent 5K, 10K, half marathon, and marathon times from anchor race results using Riegel’s formula.

Last reviewed 28 August 2026

Equivalent 5K, 10K, half marathon, and marathon times using Riegel’s formula (exponent 1.06).

Interactive calculator

Enter any time not in the table. The reference chart below stays even pace at 42.195 km, 21.0975 km, or your chosen distance.

Predicted equivalent

6:41

Mile

Your splits

Split times to the finish
Marker	Time
Mile	6:41
5K	22:13
Half marathon	1:42:14
Marathon	3:33:09

These times are Riegel estimates, not guarantees. A 46:20 at 10 km scales to other distances with exponent 1.06.

RUNNERS LAB

Race equivalent times

Equivalent race times using Riegel’s formula (exponent 1.06). Planning estimates — not measurements.

5K time	10K	Half	Marathon
15:00	31:16	1:09:00	2:23:52
15:30	32:19	1:11:18	2:28:40
16:00	33:22	1:13:36	2:33:27
16:30	34:24	1:15:54	2:38:15
17:00	35:27	1:18:12	2:43:03
17:30	36:29	1:20:30	2:47:51
18:00	37:32	1:22:48	2:52:38
18:30	38:34	1:25:06	2:57:26
19:00	39:37	1:27:24	3:02:14
19:30	40:39	1:29:42	3:07:02
20:00	41:42	1:32:00	3:11:49
20:30	42:44	1:34:18	3:16:37
21:00	43:47	1:36:36	3:21:25
21:30	44:50	1:38:54	3:26:13
22:00	45:52	1:41:12	3:31:00
22:30	46:55	1:43:30	3:35:48
23:00	47:57	1:45:48	3:40:36
23:30	49:00	1:48:06	3:45:23
24:00	50:02	1:50:24	3:50:11
24:30	51:05	1:52:42	3:54:59
25:00	52:07	1:55:00	3:59:47
25:30	53:10	1:57:18	4:04:34
26:00	54:12	1:59:36	4:09:22
26:30	55:15	2:01:54	4:14:10
27:00	56:18	2:04:12	4:18:58
27:30	57:20	2:06:30	4:23:45
28:00	58:23	2:08:48	4:28:33
28:30	59:25	2:11:06	4:33:21
29:00	1:00:28	2:13:24	4:38:09
29:30	1:01:30	2:15:42	4:42:56
30:00	1:02:33	2:18:00	4:47:44
30:30	1:03:35	2:20:18	4:52:32
31:00	1:04:38	2:22:36	4:57:19
31:30	1:05:41	2:24:54	5:02:07
32:00	1:06:43	2:27:12	5:06:55
32:30	1:07:46	2:29:30	5:11:43
33:00	1:08:48	2:31:48	5:16:30
33:30	1:09:51	2:34:06	5:21:18
34:00	1:10:53	2:36:24	5:26:06
34:30	1:11:56	2:38:42	5:30:54
35:00	1:12:58	2:41:00	5:35:41
35:30	1:14:01	2:43:18	5:40:29
36:00	1:15:03	2:45:36	5:45:17
36:30	1:16:06	2:47:54	5:50:05
37:00	1:17:09	2:50:12	5:54:52
37:30	1:18:11	2:52:30	5:59:40
38:00	1:19:14	2:54:48	6:04:28
38:30	1:20:16	2:57:06	6:09:15
39:00	1:21:19	2:59:24	6:14:03
39:30	1:22:21	3:01:42	6:18:51
40:00	1:23:24	3:04:00	6:23:39

RUNNERS LAB

From half marathon time

Half marathon anchor times from 1:20 to 2:30 in 5-minute steps.

Half time	5K	10K	Marathon
1:20:00	17:23	36:15	2:46:48
1:25:00	18:29	38:31	2:57:13
1:30:00	19:34	40:47	3:07:39
1:35:00	20:39	43:03	3:18:04
1:40:00	21:44	45:19	3:28:30
1:45:00	22:50	47:35	3:38:55
1:50:00	23:55	49:51	3:49:21
1:55:00	25:00	52:07	3:59:46
2:00:00	26:05	54:23	4:10:12
2:05:00	27:10	56:39	4:20:37
2:10:00	28:16	58:55	4:31:02
2:15:00	29:21	1:01:11	4:41:28
2:20:00	30:26	1:03:27	4:51:53
2:25:00	31:31	1:05:43	5:02:19
2:30:00	32:36	1:07:59	5:12:44

Related charts

Use this chart

This chart is free to use in articles, training plans, coaching materials, and educational content. Please credit RunnersLab.app.

Planning estimates for equivalent race times at other distances, using Peter Riegel’s power-law model with exponent 1.06.

Table A anchors from 5K times (15:00–40:00). Table B anchors from half marathon times (1:20–2:30). Use the race time predictor for a custom input.

Method

Riegel formula: T2 = T1 × (D2 ÷ D1)^1.06. T1 and D1 are your known race. T2 is the predicted time at distance D2.

Exponent 1.06 is the usual road-running value. See Riegel, P. S. (1981), American Scientist, and /methodology on this site.

Full methodology →

Limits

Planning estimate only — not a fitness test. Heat, hills, training focus, and large distance jumps reduce accuracy.

For VDOT-based equivalents, see the race equivalent calculator (Daniels). This chart uses Riegel only.

FAQ

Can I download this table as CSV or JSON?

Yes. Use Download CSV for spreadsheets and Excel, or Download JSON for programmatic use. Both files include the full table on this page with source URL and last-updated date.

Can I cite this page?

Yes. Link to this URL and credit RunnersLab.app. CSV and JSON downloads include the source URL and update date for attribution.

What does a 20:00 5K predict for a half marathon?

About 1:32:30 under Riegel (1.06) — a planning estimate, not a guarantee.

What does a 1:45 half marathon predict for a marathon?

About 3:38:30 under Riegel — assumes similar training and conditions.

Is Riegel the same as VDOT?

No. Riegel is a simple power law between two distances. VDOT uses Daniels’ oxygen model. Both are estimates.