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Calcimator

Interval Training Calculator

Design structured interval workouts for VO2max, threshold, and speed sessions. Get target paces, work and rest durations, and total session time.

Inputs

meters

Results

Target Work Pace

7:19

Target Work Pace4:33
Session TypeVO2max Intervals
Target HR Zone92-97%
Work Interval Duration3:38
Rest Duration3:38
Work:Rest Ratio1:1
Total Interval Distance4,800 m
Total Work Time21:48
Total Rest Time18:10
Full Session (incl. warmup/cooldown)59:58
How to Use This Calculator
  1. Select the Session Type: VO2max Intervals, Threshold/Tempo, or Speed/Repetition.
  2. Enter your Current Easy Pace in minutes and seconds per mile.
  3. Set the Interval Distance in meters and the Number of Intervals.
  4. Review the Target Work Pace, Interval Duration, Rest Duration, and Work:Rest Ratio.
  5. Check Total Interval Distance and Total Session Time to plan your workout structure.

What each input means

Session Type
VO2max: hard 3-5 min reps with equal rest. Threshold: comfortably hard with short rest. Speed: all-out short reps with long rest.
Current Easy Pace Minutes
Minutes portion of your current easy/conversational pace per mile. Interval paces are calculated from this baseline.
Current Easy Pace Seconds
Seconds portion of your easy pace per mile.
Interval Distance
Distance per interval repetition. Common: 200m (speed), 400m (VO2max/speed), 800m-1600m (VO2max), 1600m-3200m (threshold).
Number of Intervals
Total number of work repetitions. Typical: 4-8 for VO2max, 3-5 for threshold, 8-16 for speed.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Session Type = 0, Current Easy Pace Minutes = 8, Current Easy Pace Seconds = 30, Interval Distance = 800 = 5 input(s) provided
  2. Calculate Target Work Pace
    Target Work Pace = formatPace(workPaceSecPerMile)
    7:19 = 7:19
  3. Calculate Target Work Pace
    Target Work Pace = formatPace(workPaceSecPerKm)
    4:33 = 4:33
  4. Calculate Session Type
    VO2max Intervals = VO2max Intervals

Engine last updated . Checked against 1 independently-derived test — how we verify calculators.

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