Yasso 800 Calculator

What is Yasso 800?

The Yasso 800 is a speed workout where you run 800-meter repeats at a specific pace with recovery jogs in between. The workout was popularized by Bart Yasso, former Chief Running Officer at Runner's World magazine. The brilliant simplicity of the workout lies in its formula: the minutes and seconds of your 800m time directly translate to the hours and minutes of your predicted marathon finish time.

How It Works

The formula is straightforward:

• Run 10 x 800m repeats
• Take a 400m recovery jog between each repeat (typically 1:30-2:00 minutes)
• Your 800m time in minutes:seconds predicts your marathon time in hours:minutes
• Example: 3:30 for 800m → 3:30:00 marathon capability
• Example: 4:15 for 800m → 4:15:00 marathon capability

How to Do the Workout

1. Warm up with 1-2 miles of easy running and dynamic stretches
2. Run your first 800m at target pace
3. Recover with a 400m jog (should take 1:30-2:00 minutes)
4. Repeat for a total of 10 x 800m (start with fewer if you're new to the workout)
5. Cool down with 1-2 miles of easy running

Progressive Build-Up

Don't jump straight to 10 repeats. Build gradually over several weeks:

• Weeks 1-2: 4 x 800m
• Weeks 3-4: 5-6 x 800m
• Weeks 5-6: 7-8 x 800m
• Weeks 7+: 9-10 x 800m

Do this workout once per week during your marathon training cycle, typically starting 8-12 weeks before your marathon.

Accuracy and Limitations

The Yasso 800 is a training tool, not a precise scientific prediction. It works best when:

• You complete all 10 repeats at consistent pace (not just the first few)
• You're doing appropriate marathon-specific training (long runs, tempo runs, etc.)
• You have adequate base mileage and endurance
• You're comparing similar fitness levels over time

Limitations to consider:

• Naturally speedier runners may find predictions optimistic
• Endurance-focused runners may exceed predictions
• Heat, hills, or poor pacing can affect race day performance
• Marathon success requires long runs and endurance work, not just speed

Where to Run

• Track: Most accurate - 800m is exactly 2 laps
• GPS Watch: Works well if you have consistent, flat terrain
• Measured Course: Use a known 800m segment if track isn't available

Training Tips

• The recovery jog is crucial - don't skip it or walk instead
• Consistency matters more than pushing for your fastest possible time
• If you can't maintain pace through all 10 repeats, you started too fast
• Save this workout for your marathon-specific training phase, not year-round
• Combine with long runs, tempo runs, and easy miles for complete marathon preparation
• Stop the workout if you feel pain or your form deteriorates significantly

Alternative Uses

While designed for marathon training, the Yasso 800 can also:

• Build general speed and running economy
• Improve lactate threshold
• Serve as a fitness benchmark over time
• Provide mental toughness training for race-pace discomfort