Run/Walk Calculator
Predict your finish time from fixed run and walk intervals and two paces, or flip it around and solve the run pace a goal finish time needs.
Mode
Interval ratio presets
Defaults to a brisk walk, around 9:30 /km. Edit it to match your own walk pace. Uses the same unit as run pace above.
Finish time
Average pace: 6:29 /km for 10K.
Cycles: 12 full, plus one shorter finishing cycle. Total time walking: 12:40.
This estimate uses a generic formula. Connect your Strava/Whoop/Garmin data for a version personalised to your actual training.
Get early accessThe idea
Alternate a fixed run interval with a fixed walk interval, repeated for the whole distance. Because both the time and the distance of one cycle scale together no matter how many times you repeat it, the cycle has one true long run average pace: the total time in a cycle divided by the distance that cycle covers. Predict mode walks that cycle forward until it reaches your distance, including whatever partial run or walk segment finishes the effort, so the finish time and total time walking are exact, not just the asymptotic average.
Predict or solve for a goal
Predict mode takes your run pace, walk pace, interval lengths, and distance, and tells you what finishes. Goal mode flips the question: given a goal finish time, a walk pace, and the run to walk interval ratio, it solves directly for the run pace you need to hit that goal. If the ratio leans heavily enough on walking that walking alone, at that walk pace, would already meet or beat the goal, there is no run pace that solves it. The calculator says so rather than returning a number that implies running slower than you walk.
Where this method comes from
Jeff Galloway popularised structured run/walk intervals through his Run Walk Run method, used by recreational runners and some elite marathoners alike to manage fatigue and reduce injury risk over long distances. The approach is his; the maths here is just arithmetic over whatever interval and pace numbers you choose, not a claim about what ratio is best for you.
Sources and limitations: see our methodology.
Worked example
Take a 4 to 1 plan: 4:00 running at 6:00 /km, then 1:00 walking at 9:30 /km, repeated over a 10K.
FAQ
What counts as the run and walk interval here?
Both are time, not distance: how long you run before switching to walking, and how long you walk before switching back to running, entered in minutes and seconds. The preset chips (4:1, 3:1, 1:1, and 30 seconds/30 seconds) fill in common Galloway style ratios, and you can edit either field to any value.
Why does the average pace use the whole cycle instead of just the run pace?
Because a run/walk plan's real long run pace is set by both phases together, not the run pace alone. The average pace here is the total time in one cycle divided by the total distance that cycle covers, which is also the exact long run average you would see over many repeated cycles.
Why would goal mode say there is no run pace to solve for?
If your walk pace and interval ratio are slow enough that walking alone, within its share of the cycle, would already meet or beat the goal time, the equation has no positive run pace solution. Try a shorter goal time, a faster walk pace, or a ratio that leans more on running.
Does this calculator account for a partial last interval?
Yes. Predict mode simulates full run and walk cycles up to your distance, then works out exactly how far into the final run or walk segment the finish line falls, rather than assuming the distance divides evenly into whole cycles.