Pace Converter

By Thomas Mortelmans

🎯 What It Does

This calculator converts between different pace and speed units. It's like a currency converter, but for running/cycling speed:

Use it when:

Your watch shows min/km, race is in min/mile
Treadmill shows mph, you train in km/h
Comparing your pace to others using different units
Setting paces for workouts in different units

Example conversions:

5:00 /km = 8:03 /mile = 12 km/h = 7.5 mph

Triathlon - From Capacity to Control (4 Weeks):

Fitness isn’t the problem. Durability is.

This 4-week triathlon block is built to improve how long you can hold quality across swim, bike, and run as fatigue accumulates. The goal is control, not maximal effort.

Use this when you feel fit, but execution falls apart late. View Plan here

📊 How to Use It

Two Modes: Running and Swimming

Running Mode:

Converts pace (min/km, min/mi)
Converts speed (km/h, mph, m/s)
Enter any value, get all others

Swimming Mode:

Pace per 100m
Pace per 100yd
Pace per 25m (one length)
Pace per 25yd
Accounts for pool length difference

How to Use (Running):

Just enter ANY value:

Type "5:00" in min/km → All others update
Type "12" in km/h → All others update
Type "7.5" in mph → All others update

All fields update instantly!

Example Conversions:

Easy Run (5:30 /km):

Pace (min/km): 5:30
Pace (min/mile): 8:51
Speed (km/h): 10.9
Speed (mph): 6.8
Speed (m/s): 3.03

Marathon Pace (4:00 /km):

Pace (min/km): 4:00
Pace (min/mile): 6:26
Speed (km/h): 15.0
Speed (mph): 9.3
Speed (m/s): 4.17

Sprint (3:00 /km):

Pace (min/km): 3:00
Pace (min/mile): 4:49
Speed (km/h): 20.0
Speed (mph): 12.4
Speed (m/s): 5.56

Swimming Conversions:

Fast Swimmer (1:30 /100m):

Per 100m: 1:30
Per 100yd: 1:22 (faster - shorter distance)
Per 25m: 0:23 (one length)
Per 25yd: 0:21

Note: 100 yards = 91.44 meters, so pace per 100yd is faster!

If you want to see what I read to keep my own work sharp outside this newsletter, this is the list.

🔬 Scientific Basis

The Math:

Pace to Speed:

Speed (km/h) = 60 / Pace (min/km)

Example: 5:00 /km
= 60 / 5
= 12 km/h

Speed to Pace:

Pace (min/km) = 60 / Speed (km/h)

Example: 12 km/h
= 60 / 12
= 5 min/km

Kilometer to Mile:

1 mile = 1.60934 km

Pace (min/mile) = Pace (min/km) × 1.60934

Example: 5:00 /km
= 5.0 × 1.60934
= 8.05 minutes
= 8:03 /mile

Speed Conversions:

km/h to mph: divide by 1.60934
mph to km/h: multiply by 1.60934
km/h to m/s: divide by 3.6

Swimming (meters to yards):

1 yard = 0.9144 meters
100 yards = 91.44 meters

Pace per 100yd = Pace per 100m × 0.9144

Example: 1:30 /100m
= 90 seconds × 0.9144
= 82.3 seconds
= 1:22 /100yd

Why It Matters:

International Races:
- USA: Miles
- Rest of world: Kilometers
- Need to convert for pacing
Training Zones:
- Coach prescribes: 4:30 /km
- Your watch: Shows min/mile
- Need conversion: 7:15 /mile
Treadmills:
- US treadmills: mph
- European: km/h
- Conversion essential
Swimming Pools:
- Short course: 25m or 25yd
- Long course: 50m
- Olympic: 50m
- Paces not directly comparable!

Common Benchmarks:

Running Paces:

World-class marathon: 2:55 /km (17:24 /mi)
Elite marathon: 3:00 /km (20 km/h)
Good marathon: 4:15 /km (14 km/h)
Average marathon: 5:30 /km (11 km/h)
Jogging: 6:30 /km (9 km/h)
Walking: 8:00 /km (7.5 km/h)

Swimming Paces (100m):

Olympic: 0:55-1:05 /100m
Elite age-group: 1:10-1:25 /100m
Good: 1:30-1:45 /100m
Average: 1:50-2:10 /100m
Beginner: 2:15-2:45 /100m

Disclaimer

The information provided in this newsletter is for educational purposes only and does not constitute medical advice. Exercise physiology is highly individual; what works for elite populations may not apply to everyone. Always consult with a physician before making significant changes to your training, nutrition, or supplementation protocols. The Scientist's Notebook and ESQ Coaching accept no liability for injuries or health issues arising from the application of these concepts.