Skip to content
RUNNERS LAB

Yasso 800
Calculator

Map a marathon goal H:MM to 800m repeats in MM:SS. A heuristic, not a predictor.

Last reviewed 19 August 2026

Yasso 800s say a 3:10 marathon maps to 3:10 800s — hours and minutes become minutes and seconds. Ten of those with recovery is the workout. It is a heuristic Bart Yasso popularised, not Riegel, not VDOT, and not a promise you will run 3:10.

Marathon goal

Enter the finish time you want to run.

Yasso 800

3:10

  • Heuristic, not a predictor
  • 10 × 800m with recovery

What this result means

The mapping is a clock trick: 3 hours 10 minutes → 3 minutes 10 seconds per 800 m. Seconds on the marathon clock are ignored in the classic telling; this implementation uses hours and minutes from the rounded marathon time.

Marathon potential and the race predictor estimate a marathon from a shorter race. Yasso goes the other way: from a marathon goal down to a track session. Link them, do not mix the formulas.

3:00:00 marathon → 3:00 800s. 4:00:00 → 4:00 800s. 2:50:00 → 2:50 800s. Ten repeats with a recovery jog between is the usual set; recovery is not computed here — use 800m repeats if you want a session clock at that 800 time.

If you cannot hold 3:10 800s, the heuristic says the 3:10 marathon is not in range yet. That is folklore plus a workout, not a lab result.

Calculation method

800m target seconds = (marathon hours × 60) + marathon minutes, using the displayed H:MM of the goal time. Cite the workout as popularised by Bart Yasso / Runner’s World, not as a peer-reviewed model.

Deterministic trick. Not an endurance formula.

Plenty of people run the Yasso times and miss the marathon, and the reverse. Heat, long runs, and fuelling dominate. Treat it as a session idea.

Full methodology →

Frequently asked questions

What are Yasso 800s for a 3:10 marathon?

3:10 per 800 m. Typically 10 repeats with recovery. This page only maps the time.

Does this predict my marathon?

No. It is a heuristic. Use Riegel or VDOT for estimates, then train.

How much rest between Yasso 800s?

Commonly a 400 m jog. Set rest on the 800m repeats calculator if you want a session total.

You may also want