Interval Running Pace Calculator

Calculate interval running pace, split times, recovery pace, and workout distance.

Rep split

1:41

400 m at target pace

Workout distance

3.2 km

8 repeats

Total time

23.9 min

Work plus recoveries

Recovery

90 sec

Between repeats

Interval inputs

Plan interval running split, workout distance, and total time.

Repeat distance

Repeats

Work pace

min/km

Recovery

sec

Related calculators

Exercise Calorie CalculatorEstimate calories burned from exercise type, body weight, duration, and intensity.
Protein Intake CalculatorEstimate daily protein needs based on weight, activity level, fitness goal, and diet pattern.
Water Intake CalculatorEstimate daily water needs from body weight, activity, climate, and lifestyle factors.
비만도 계산기BMI 및 비만도 계산
Sleep CalculatorPlan wake-up or bedtime using sleep cycles, target sleep duration, and daily routine assumptions.
Gym PT vs Home Training CalculatorGym PT vs Home Training Calculator helps Compare two everyday planning options using upfront cost, recurring cost, and time horizon assumptions.

What is the interval running pace calculator?

This calculator derives training paces from a recent race result or a 5K time trial. The Korean source page is based on the Jack Daniels running formula and VDOT concept, then explains how to use Easy, Marathon, Threshold, Interval, and Repetition paces safely.

Rather than showing one generic target pace, it separates aerobic base building from threshold development and high-intensity repeats. That matters because interval pace should be hard enough to stimulate adaptation but not so hard that every workout becomes a race.

2026 Korea running context

The source notes running crews up 40% versus 2024, more than 3,000 running crews, trail running participation growing about 30% annually, and women accounting for more than 40% of marathon participants.

Training zones

Aerobic and threshold zones

E pace means Easy running at vVO2max 65% to 75% and max heart rate 65% to 79%. It should feel conversational and usually lasts 20 to 90 minutes, 3 to 5 times per week.
M pace means Marathon pace at vVO2max 75% to 84% and max heart rate 80% to 85%. It is commonly used as a segment inside a weekly long run.
T pace means Threshold or tempo pace at vVO2max 83% to 88% and max heart rate 86% to 90%. Use a 20-minute tempo run or 1000 to 1600 m cruise intervals, 1 to 2 times per week.

High-intensity zones

I pace means Interval pace at vVO2max 95% to 100% and max heart rate 95% to 100%. Typical work is 400 to 1200 m repeats with recovery similar to the work duration.
R pace means Repetition pace at vVO2max 105% to 110%. It is pace-based rather than heart-rate based, often 200 to 400 m repeats with recovery 2 to 3 times the work duration.
High-intensity T, I, and R work should stay within about 20% of weekly distance, leaving about 80% as Easy running under the 80/20 rule.

Weekly use and injury prevention

Example week

Monday Easy 30 to 50 minutes, Tuesday 400 m x 8 to 10 at I pace, Wednesday Easy 40 to 60 minutes.
Thursday uses a 20-minute tempo run or cruise intervals, Friday is rest or Easy 20 minutes.
Saturday is a 60 to 120 minute long run with an optional M-pace segment, and Sunday is rest.

Safety rules

Beginners should usually start interval workouts only after 3 to 6 months of consistent running.
The 10% rule says weekly distance should not increase by more than about 10% at once.
Lower-body strength training 2 to 3 times per week can reduce injury risk by 30% to 50%.
Seven to 9 hours of sleep supports recovery; lack of sleep raises injury risk about 1.7x.
Replace running shoes every 500 to 800 km, and in Korean summer humidity slow pace by about 5 to 10 seconds per km for each 5 C above 15 C.