How it works
800 m target = marathon goal time ÷ 60
The conversion is one division by 60. An hour contains 60 minutes and a minute contains 60 seconds, so dividing a duration by 60 shifts its units down one step — which is how H hours and MM minutes of marathon become MM minutes and SS seconds of 800 m repeat. A 3:45:00 goal is 13,500 seconds; divided by 60 it becomes 225 seconds, which reads 3:45 on a stopwatch. The tool then spreads that repeat time across 0.8 km to express it as pace per kilometer and per mile. The classic protocol builds across a training block from 4–6 repeats toward the benchmark session of ten 800s, each followed by a jog recovery lasting exactly as long as the repeat; running the full set on target two or three weeks out is the strongest sign the goal will hold.
Sources
- Yasso 800s Bart Yasso, Runner’s World — the Yasso 800s workout: 800 m repeats whose min:sec match the marathon goal’s hours:minutes.
- Interval training basis Repeat 800 m intervals at goal-derived pace develop the aerobic power and pacing needed for the marathon; the rule is a practical heuristic, not a physiological model.
- Recovery convention The classic protocol uses a jog recovery of equal duration to each 800 m repeat.
FAQ
Where does the Yasso 800 rule come from?
Bart Yasso of Runner’s World noticed that the time he could average for a set of 800s — read as minutes and seconds — kept matching his marathon finishes read as hours and minutes. The magazine popularized the trick and the name stuck. It is well-tested folklore, not physiology, and this page treats it that way.
How is the workout structured?
Two laps of a standard track at your target figure, a recovery jog lasting as long as the repeat itself, then repeat. Early in a block runners typically manage 4–6; the benchmark session is ten. Completing the whole set on target matters more than crushing the first three and fading.
How much faith should the prediction get?
A moderate amount. The rule assumes marathon-grade endurance is already in place; speed-leaning runners routinely nail every 800 and still fade over the final 10 km, because long runs — not intervals — carry the closing miles. Weigh it alongside a dedicated predictor and the evidence of your training block.
Can I run the calculation in reverse?
Yes. Time an honest Yasso session, average the 800 splits, and read the digits back the other way: repeats averaging 3:38 hint at a marathon in the neighborhood of 3:38:00. It is a grounded way to pick a goal before you commit to a registration and a pace plan.
Why must the recovery jog equal the repeat time?
Because the recovery is part of the calibration. Rest longer and the session stops simulating late-race fatigue, so the prediction flatters you; rest shorter and it becomes a different, harder workout that under-reports your fitness. Easy jogging, equal duration — that is the deal the rule was built on.
Is this workout enough marathon training?
No. It is one quality session per week at most, riding on top of easy mileage, long runs, and fueling practice. The 800s sharpen speed and, late in the block, deliver a confidence check — but the marathon itself is decided by the aerobic base underneath them.
The Yasso rule is a coaching shortcut with a decent track record, not a guarantee — endurance, weather, pacing discipline, and fueling decide the actual finish. Use the target as a workout benchmark, and read this page as general training information rather than medical or coaching guidance.