Why you can't just average the two paces
This is the mistake almost every run-walk estimate makes. Run 4 minutes at 9:00 per mile and walk 1 minute at 15:00 per mile, and the time-weighted average of those two paces is 10:12. Your actual average is 9:47. The gap matters: over a marathon it is eleven minutes.
Paces are inverted units — minutes per mile — so they do not average the way speeds do. What you have to average is distance covered:
Cycle distance = run seconds ÷ run pace + walk seconds ÷ walk pace
Average pace = cycle seconds ÷ cycle distance
In the example above, 4 minutes of running covers 0.444 miles and 1 minute of walking covers 0.067, so each 5-minute cycle moves you 0.511 miles — and 300 ÷ 0.511 = 9:47 per mile.
Run-walk ratio chart
Average pace and marathon finish for each common ratio, with a 9:00 running pace and a 15:00 walk. Change the inputs above for your own numbers.
| Ratio | Time running | Average pace | Marathon |
|---|---|---|---|
| 30 sec : 30 sec | 50% | 11:15 /mile | 4:54:58 |
| 1 : 1 | 50% | 11:15 /mile | 4:54:58 |
| 2 : 1 | 67% | 10:23 /mile | 4:32:16 |
| 3 : 1 | 75% | 10:00 /mile | 4:22:11 |
| 4 : 1 | 80% | 9:47 /mile | 4:16:29 |
| 6 : 1 | 86% | 9:33 /mile | 4:10:16 |
| 9 : 1 | 90% | 9:23 /mile | 4:05:48 |
Does walking cost you time?
Less than most runners assume. Hottenrott and colleagues (2016) put 42 non-elite runners through a marathon in a randomised trial, half using a run/walk strategy and half running throughout. The run/walk group finished in 4:14:25 and the running-only group in 4:07:40 — about seven minutes apart, which was not statistically significant (p = 0.377) across a group that varied by twenty minutes either way.
What did differ: the run/walk group reported significantly less muscle pain and fatigue afterwards (p = 0.006). For a runner whose marathon falls apart in the last 10 km, that is the whole argument — you are trading a few minutes you might not lose anyway against arriving at 30 km with legs that still work.
What run-walk does not do
The same study measured cardiac biomarkers after the finish and found the run/walk strategy did not reduce the load on the cardiovascular system. Both groups showed the same reversible rise in B-type natriuretic peptide and muscle markers that any marathon produces, returning to baseline four days later.
So run-walk is a strategy for your legs, not your heart. If you have been told to limit cardiovascular strain, walk breaks are not the adjustment that does it, and that is a conversation for a doctor rather than a calculator.
Choosing a ratio
- Start the breaks from the first mile. The method works by saving your legs before they are tired. Walking from 20 miles because you are struggling is not a run-walk strategy, it is the thing a run-walk strategy exists to prevent.
- Faster runners take shorter breaks. At 7:00 pace a full minute of walking costs more than it does at 11:00, so 9:1 or 6:1 suits faster runners while 2:1 and 1:1 suit slower ones and beginners.
- Walk with purpose. The chart assumes a brisk 15:00 mile. A 20:00 mile stroll changes a 4:1 ratio from 9:47 to 10:07 per mile.
- Rehearse it. Run your long runs at the ratio you plan to race. The right ratio is the one you can still hold at 35 km.
Pacing the breaks on hills
Walk breaks and hills interact: many run-walkers take their break on the climbs, where the pace difference between running and walking is smallest. The grade-adjusted pace calculator shows what a hill is costing you, which is a reasonable way to decide where the breaks go.
Frequently asked questions
How do I work out my average pace with walk breaks?
Not by averaging the two paces — that gives the wrong answer. Work out how far you cover in one run/walk cycle, then divide the cycle's total time by that distance. Running 4 minutes at 9:00/mile and walking 1 minute at 15:00/mile averages 9:47 per mile, not the 10:12 you get by weighting the paces.
Does taking walk breaks make you slower?
Less than runners expect. In a randomised trial of 42 non-elite marathon runners (Hottenrott et al., 2016), the run/walk group finished in 4:14:25 and the running-only group in 4:07:40 — a difference that was not statistically significant. The run/walk group reported significantly less muscle pain and fatigue afterwards.
What run-walk ratio should I use?
It depends on your pace and how long you are out. Common starting points are 4:1 and 2:1 for marathon pace, 30 seconds on and 30 seconds off for beginners, and 9:1 for runners who want only a short break. Try a ratio on a long run before you race it — the right one is whichever you can hold to the end.
Should I start walk breaks from the beginning of a race?
That is the usual advice, and the calculator assumes it: the method works by saving your legs before they are tired, not by rescuing them afterwards. Starting breaks at mile 20 because you are struggling is a different thing from a run-walk strategy.
Does run-walk reduce the strain on your heart?
No. The same trial measured cardiac biomarkers after the marathon and found the run/walk strategy did not reduce the load on the cardiovascular system. What it reduced was muscle discomfort. Both groups showed the reversible rise in cardiac markers that any marathon produces.
Sources
The formula on this page comes from the published work below. We check the numbers against the worked examples in these sources with automated tests, and re-read the page against them when we review it.
- Hottenrott K, Ludyga S, Schulze S, Gronwald T, Jäger FS. Does a run/walk strategy decrease cardiac stress during a marathon in non-elite runners? J Sci Med Sport. 2016;19(1):64–68. pubmed.ncbi.nlm.nih.gov/25467199/
- World Athletics. Technical information and competition rules — standard road race distances, including the marathon at 42.195 km. worldathletics.org/about-iaaf/documents/technical-information
General fitness information, not medical advice. Results are estimates; check with a doctor or qualified coach before major changes to diet or training. Formula and copy last reviewed 12 October 2026.