Interval Training Calculator Formula

Understand the math behind the interval training calculator. Each variable explained with a worked example.

Use the Interval Training Calculator

Formulas Used

Total Session

total_session_min = round((warmup_min + interval_block_min + cooldown_min) * 10) / 10

Work:Rest Ratio

work_rest_ratio = round(work_duration_sec / rest_duration_sec * 100) / 100

Total Work Time

total_work_min = round(total_work_sec / 60 * 10) / 10

Total Rest Time

total_rest_min = round(total_rest_sec / 60 * 10) / 10

Variables

VariableDescriptionDefault
num_intervalsNumber of Intervals8
work_duration_secWork Duration(sec)60
rest_duration_secRest Duration(sec)60
warmup_minWarm-Up(min)10
cooldown_minCool-Down(min)5
total_work_secDerived value= num_intervals * work_duration_seccalculated
total_rest_secDerived value= (num_intervals - 1) * rest_duration_seccalculated
interval_block_minDerived value= (total_work_sec + total_rest_sec) / 60calculated

How It Works

How to Plan Interval Training

Interval training alternates high-intensity work periods with rest or low-intensity recovery.

Key Variables

  • Work Duration: Time spent at high intensity
  • Rest Duration: Recovery between intervals
  • Work:Rest Ratio: Determines the energy system targeted

    • Work:Rest Guidelines

  • 1:3-1:5 for power/speed (sprints, 10-30 sec)
  • 1:1-1:2 for VO2max (60-120 sec intervals)
  • 2:1-3:1 for lactate threshold (longer tempo intervals)

    • Worked Example

    8 x 60-second intervals with 60-second rest, 10 min warmup, 5 min cooldown.

    num_intervals = 8work_duration_sec = 60rest_duration_sec = 60warmup_min = 10cooldown_min = 5
    1. 01Total work = 8 * 60 = 480 seconds = 8.0 min
    2. 02Total rest = 7 * 60 = 420 seconds = 7.0 min (7 rest periods between 8 intervals)
    3. 03Interval block = (480 + 420) / 60 = 15.0 min
    4. 04Total session = 10 + 15.0 + 5 = 30.0 min
    5. 05Work:Rest ratio = 60/60 = 1.00

    Ready to run the numbers?

    Open Interval Training Calculator