Intervals
Track-workout target times across every interval distance, plus the Yasso 800 marathon predictor. Personalized to your VDOT.
No VDOT yet. Enter a recent race to generate your splits.
Workout splits
| Distance | Zone | Target time | Suggested reps | Rest |
|---|---|---|---|---|
| 200m | Repetition | 0:44 | 8-12x | 1:28 jog |
| 400m | Repetition | 1:28 | 6-10x | 2:56 jog |
| 600m | VO2max | 2:29 | 5-8x | 2:29 jog |
| 800m | VO2max | 3:18 | 4-6x | 3:18 jog |
| 1000m | VO2max | 4:08 | 3-5x | 4:08 jog |
| 1200m | VO2max | 4:57 | 3-4x | 4:57 jog |
| 1600m | Threshold | 7:21 | 2-4x | 1:00 jog |
| 2000m | Threshold | 9:11 | 2-3x | 1:00 jog |
Target times are calculated for the midpoint of each pace range. Build up volume over weeks rather than chasing every rep at the prescribed pace.
Yasso 800s
How this calculator works
- VDOT and equivalent training paces
VDOT is a single number that summarizes your aerobic fitness from a recent race performance. Daniels' tables map VDOT to equivalent times at every standard distance and to recommended paces for easy, marathon, threshold, interval, and repetition work. PaceCalc estimates VDOT from your inputs, then surfaces those equivalent paces.
Jack Daniels, Daniels' Running Formula, 3rd edition, Human Kinetics, 2013. Tables for VDOT and zone-based pacing.
- Interval target paces follow Daniels VDOT zones (Interval and Repetition). Recovery durations follow standard work:rest ratios for the zone (typically 1:1 for Interval; longer for Repetition).
Frequently asked
- What are Yasso 800s?
- Yasso 800s are a popular marathon workout where your 800m repeat time (in minutes:seconds) mirrors your marathon goal time (in hours:minutes). For example, a 3:30 marathon goal means running 800m repeats in 3:30. Do 10 repeats with equal-time jog recovery.
- How do I know which workout zone to train in?
- Each zone serves a different purpose: Repetition (200-400m) builds speed and form, VO2max intervals (600-1200m) improve oxygen uptake, and Threshold repeats (1600-2000m) increase sustainable pace. A balanced training plan includes all zones.
- How accurate are the target splits?
- Splits are derived from your VDOT (estimated from your race result) using Jack Daniels' methodology. They're excellent starting points but should be adjusted based on training conditions, fatigue, and how you feel during the workout.
- How many reps should I do?
- The suggested rep ranges are guidelines. Start at the lower end and progress as your fitness improves. Total hard running in a VO2max session should be 15-20 minutes; threshold work can be 20-40 minutes.
- What's the right rest between intervals?
- Rest depends on the zone: VO2max intervals use equal-time jog recovery (run 3 min, jog 3 min), Repetition reps use 2-3x the work time, and Threshold repeats use short 1-minute jogs. Active jogging recovery is better than standing.