Running Interval Calculator — Paces and Session Plan

Give it your goal race, goal time and running level and it works out your training paces — interval, tempo, race and easy — then fills in an interval session to match. Adjust the reps, recovery, warm-up and cool-down and the table of per-rep targets, elapsed time and session total updates as you go.

How to use

  1. Pick your goal race, goal time and running level.
  2. Press 'Fill the session from this goal' to load reps, distance and recovery.
  3. Tweak reps, recovery, warm-up and cool-down if you want.
  4. Read the target and elapsed time for each segment and copy them onto your watch.

You can't watch a screen mid-run, so this is a plan you check before you start, not a live timer. If you have a running watch, enter the rep and recovery durations there as an interval workout.

FAQ

Where do the training paces come from?

Your goal time is converted into equivalent times at other distances with Riegel's formula. Interval pace is your 3 km race pace, tempo (threshold) is your 10 km race pace, and easy is 75 seconds per kilometre slower than threshold.

How long should recovery be?

It depends on the goal. For speed work with short, fast reps, use a generous 1:1 to 1:2 work-to-rest ratio; for endurance-focused sessions, tighten it to 2:1 or more. The ratio is always on screen, and choosing the beginner level gives you longer recoveries.

Is there a recovery after the last rep?

No. Recovery only goes between reps; after the final one the plan moves straight to the cool-down, so the session total is not inflated.

What should my 400 m split be?

It is printed on each fast row of the table. At an interval pace of 4:30/km, for instance, 400 m is 1:48.

Related tools

  • BMI & BMR Calculator — Body mass index, basal metabolic rate, and daily calorie needs.
  • 1RM Calculator — Estimate your one-rep max and a per-set weight table from a lift.
  • TDEE Calculator — Find the calories you burn daily (TDEE) and your BMR, plus target calories and macros for any goal.
  • Running Pace Calculator — Enter two of pace, finish time and distance to get the third, plus treadmill speed and splits.