What are Yasso 800s?
Yasso 800s are a marathon workout invented by Bart Yasso of Runner's World. The idea is delightfully simple: run 10 × 800 metres with an equal-duration recovery jog between each — and time them to match your marathon goal.
The trick is the unit swap. If your marathon goal is 3 hours 30 minutes, you aim to run each 800 in 3 minutes 30 seconds. A 4:00 goal means 800s in 4:00. When you can complete all ten reps at that time, comfortably, you have a strong signal that your goal is realistic.
How to do the Yasso 800s workout
- Warm up with 15–20 minutes of easy running plus a few strides.
- Run 800 m at your target time (shown above for your goal).
- Recover with an easy jog of the same duration as the rep.
- Repeat, building from 4–6 reps early in your block up to the full 10.
- Cool down with 10–15 minutes of easy running.
Run them on a track, a flat path, or a treadmill. The recovery jog matters — it keeps the session aerobic and marathon-specific rather than turning it into a pure speed workout.
Yasso 800 times by marathon goal
Your 800 target and its pace for common marathon goals. These are the exact values this calculator produces.
| Marathon goal | 800 m target | Pace / km | Pace / mile |
|---|---|---|---|
| 3:00 | 3:00 | 3:45 | 6:02 |
| 3:15 | 3:15 | 4:04 | 6:32 |
| 3:30 | 3:30 | 4:23 | 7:02 |
| 3:45 | 3:45 | 4:41 | 7:33 |
| 4:00 | 4:00 | 5:00 | 8:03 |
| 4:30 | 4:30 | 5:38 | 9:03 |
| 5:00 | 5:00 | 6:15 | 10:04 |
How accurate are Yasso 800s?
Yasso 800s are a benchmark, not a promise. They track marathon fitness well for many runners, but the marathon rewards endurance and fuelling as much as speed. Someone with fast 800s but thin long-run mileage can still fade after 30K.
Use them as a confidence check alongside the tools that gauge the other side of the equation:
- VDOT calculator: convert a recent race into equivalent paces and a marathon prediction.
- Marathon pace calculator: turn your goal into per-km and per-mile race splits.
Fit Yasso 800s into a full marathon plan
The Running Genie schedules the right workouts on the right weeks — Yasso-style intervals, long runs, and marathon-pace work — and adapts as your fitness changes.
Frequently asked questions
What are Yasso 800s?
Yasso 800s are a marathon workout created by Bart Yasso: 10 repeats of 800 metres with a recovery jog of equal duration between them. If you can run your 800s in the same minutes and seconds as your marathon goal is in hours and minutes, you are on track. A 3:30 marathon goal means 800s in 3 minutes 30 seconds.
How accurate are Yasso 800s?
They are a useful benchmark, not a guarantee. They correlate reasonably well with marathon fitness for many runners, but your result also depends on endurance, long-run training, fuelling, and race-day conditions. Treat them as a confidence check alongside your long runs.
How do I do the Yasso 800s workout?
Warm up with 15–20 minutes of easy running and strides. Run 800 m at your target time, then jog for the same duration as recovery. Repeat for 10 reps, building up to the full set over several weeks, then cool down. Early in a block, start with 4–6 reps and add one or two each week.
When should I do Yasso 800s?
They fit best in the middle-to-late phase of a marathon block, once you have an aerobic base. Run them every week or two, working up to the full 10 reps three to four weeks before race day. They complement, not replace, your long runs and marathon-pace work.
What pace are Yasso 800s?
It depends on your goal. A 4:00 marathon goal gives 800s in 4:00, a 5:00 per km (about 8:03 per mile) pace. A 3:30 goal gives 800s in 3:30, roughly 4:23 per km. This calculator shows the exact pace per km and per mile for your goal.
Related running calculators
Get a full marathon plan
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