The Complete Guide to Running Pace & Race Prediction

Last updated: 2026-06-25

What is pace

In running, pace is the time it takes to run 1 km, shown in minutes:seconds (min/km). For example, a pace of 6:00 means you run 1 km in 6 minutes, and a pace of 5:30 means 5 minutes 30 seconds per km. Unlike a car's speed (km/h), running expresses intensity as "time per distance," because it lets you compare effort intuitively over the same distance. A smaller pace number is faster, so going from 6:00 to 5:30 means you improved.

Pace and speed convert easily. Speed (km/h) = 60 ÷ pace (min/km), so a 6:00 pace is 10 km/h and a 5:00 pace is 12 km/h. Conversely, if a treadmill is set to 12 km/h, the pace is 60 ÷ 12 = 5:00. With just distance and goal time, the Running Pace Calculator shows your pace per km, speed, and split times all at once.

Why you should know your pace

Knowing your pace lets you set concrete goals. A goal of "run 10K in 50 minutes" means holding an average pace of 5:00/km, and that benchmark tells you during training whether you are too fast or too slow. In long races like the marathon, setting the wrong early pace often causes a dramatic late collapse. Holding an even pace, or running the second half slightly faster (a negative split), is known to help lower your time.

Pace is also the basis for separating training intensities. Easy recovery runs, sustained tempo runs, and short fast intervals each use different pace ranges. Once you know your goal race pace, you can set these training paces sensibly too.

Marathon race prediction: the Riegel formula

If you have a result from a distance you have already run, you can estimate a result at another distance. The most widely used method is the formula proposed by Peter Riegel.

T₂ = T₁ × (D₂ ÷ D₁)^1.06

Here T₁ and D₁ are your existing time and distance, and T₂ and D₂ are the target distance and its predicted time. The exponent 1.06 reflects the endurance decay where pace slows slightly as distance grows. If pace were perfectly constant regardless of distance, the exponent would be 1.0, but in practice average pace slows as distance increases, so 1.06 is the standard.

For example, someone who runs 10K in 45 minutes predicting a full marathon (42.195 km) gets 45 min × (42.195 ÷ 10)^1.06 ≈ 3 hours 28 minutes. This prediction assumes adequate long-run training and is more accurate when the existing and target distances are close. Predicting a full marathon from a 5K creates more error, so it is better to use a half or 10K result. Enter your existing result into the Marathon Race Time Predictor to see predicted times and paces for several distances at once.

Pace needed for common goals

A common marathon goal is the "sub" expression by finish time. Sub-3 means under 3 hours, sub-4 means under 4 hours. Dividing the full 42.195 km by your goal time gives the average pace you need.

This table assumes a perfectly even average pace. In a real race, it is safer to allow some margin for aid stations, hills, and late-race fatigue.

Calories burned running

Calories burned running are estimated from exercise intensity (MET), body weight, and time. The formula is calories (kcal) = MET × body weight (kg) × time (hours). MET (metabolic equivalent) is an intensity metric that sets resting metabolism at 1, and 1 MET is about 1 kcal/kg/hour. Running's MET rises with speed: a light jog (8 km/h) is about 8.3 MET and fast running (12.9 km/h) is about 11.8 MET.

For example, a 65 kg person running at 10 km/h for 30 minutes burns about 10.0 MET × 65 kg × 0.5 hours ≈ 326 kcal. Interestingly, calories per distance stay relatively constant regardless of speed, roughly 1 kcal per kg of body weight per km. So a 60 kg person running 5 km burns roughly 300 kcal regardless of speed. The exact value varies with terrain, wind, and individual efficiency, so treat the Running Calorie Calculator result as a reference estimate.

Treadmill conversion and incline

When running indoors on a treadmill you set intensity by speed (km/h), so converting to pace makes it easy to compare with outdoor training. As above, pace (min/km) = 60 ÷ speed (km/h). Treadmill 10.0 is 6:00/km and 12.0 is 5:00/km.

However, a treadmill has no wind resistance and the belt helps move your feet back, so the same speed is somewhat easier than flat outdoor running. That is why many runners set a 1-2% incline to match outdoor intensity. The Treadmill Pace Converter converts speed and pace both ways and also estimates a flat-ground equivalent pace based on the incline (%).

Goal setting for beginner runners

When you are just starting out, consistency matters more than speed. Run comfortably at a conversational intensity (usually 7-8 min/km) and build up to about 3 runs per week. Once you are comfortable, time a 5K and feed that result into the Riegel formula to set a 10K or half marathon goal. Don't increase weekly distance by more than 10% at once; build up gradually to avoid injury.

• Hold an easy, even pace — going out too fast early is the main cause of a late collapse.
• Plan in the order: existing result → Riegel formula → goal pace.
• Build distance and intensity gradually; recovery (easy runs) is part of training too.
• Calorie and incline conversions are for reference; consider your condition and course too.

Summary

• Pace is time per km (min/km): pace = total time ÷ distance, speed = 60 ÷ pace.
• The Riegel formula T2 = T1 × (D2 ÷ D1)^1.06 predicts other distances from an existing result.
• Calories = MET × weight × time; calories per distance are roughly 1 kcal per kg per km.
• Treadmill speed and pace convert as 60 ÷ value, and a 1-2% incline matches outdoors.

Last updated: 2026-06-25