What pace should easy runs be?

Easy runs should feel relaxed. You should be able to talk in full sentences while you run. For a runner with a 20:00 5K, that is about 5:01 per kilometer — about a minute slower than 5K race pace. Most of your weekly running, around 80 percent, should be at this easy pace. Going faster on easy days is the most common mistake runners make. It steals the energy you need for your hard days.

How fast are threshold/tempo runs?

Threshold pace, also called tempo, is 'comfortably hard.' You can hold it for a long time, but you could not chat through it. It is the fastest pace at which your body still clears lactate as fast as it builds up. For a 20:00 5K runner, that is about 4:16 per kilometer. Threshold runs raise the pace you can hold for a long race, so they matter a lot for the 10K, half, and marathon.

Training Paces Explained: The 5 Speeds Every Runner Needs

There are five training paces, and each one does a different job. From a recent 20:00 5K, they work out to about: easy 5:01, marathon 4:26, threshold 4:16, interval 3:51, and speed 3:34 per kilometer. Most of your running should be at the slow, easy end.

The table below shows all five paces for a 20:00 5K, with what each one is for. Your own paces come from your own race.

The five training paces (from a 20:00 5K)

Zone	/km	/mi	Purpose
Easy / Recovery	5:01	8:04	Build your aerobic base. Most of your week.
Marathon	4:26	7:08	Practice steady race-day rhythm.
Threshold / Tempo	4:16	6:52	Raise the pace you can hold a long time.
Interval / VO2max	3:51	6:11	Grow your engine — more oxygen power.
Speed / Repetition	3:34	5:44	Sharpen leg speed and form.

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Race Time Predictor

What are the five training paces?

Not every run should feel the same. Good training mixes slow and fast on purpose. Here are the five paces, from slowest to fastest.

1. Easy. Relaxed and conversational. You can talk in full sentences. This is your everyday pace and most of your miles.

2. Marathon. A steady, controlled pace. It is the rhythm you would hold for a long race. Harder than easy, but not a strain.

3. Threshold (tempo). "Comfortably hard." You can hold it for a while, but you could not chat. Threshold pace is the hardest effort where your body still clears lactate as fast as it makes it (Runner's World, 2024).

4. Interval. Fast and hard, run in short repeats with rest between. This pace pushes your top oxygen power.

5. Speed. Very fast, short bursts. This sharpens your leg speed and your form.

Runner running a fast, hard interval on an outdoor track. — Interval pace grows your engine: short, hard efforts with full recovery.

How each builds your projection

Your projected race time gets faster when your fitness gets better. Each pace improves a different part of that fitness.

Easy miles build the engine. Slow running grows the heart and the small blood vessels that feed your muscles. About 80% of your running should be easy. Athletes who keep most miles easy and only a small slice hard improve more than those who run "medium" all the time (Seiler, 2010).

Threshold raises your steady speed. Tempo runs lift the pace you can hold without fading. That is the pace that decides your 10K, half, and marathon.

Intervals grow your ceiling. Short, hard repeats raise your top oxygen power (VO2max). One study found hard intervals improved VO2max more than easy, steady running (Helgerud et al., 2007).

Speed work makes you smooth. Fast strides clean up your form so every other pace costs less energy.

Train all five in the right mix, and your projected time drops.

Runner holding a comfortably hard tempo effort on a riverside path. — Threshold pace is comfortably hard, the speed you can hold a long time.

How to get yours from one race

You do not need a lab or a watch. You need one honest race result.

Enter a recent 5K, 10K, or half into PIRX. The engine reads your fitness from that race and gives you all five training paces — in minutes per kilometer and per mile. The numbers in the table above are just an example for a 20:00 5K. Yours will match your own fitness.

The paces update as you do. Run a new race that is faster, and your training paces shift faster too. That keeps your easy days easy and your hard days at the right effort.

Train to hit your projection

Enter one recent race and get your projected time plus your five training paces — free, no signup, no watch.

PIRX's proprietary machine-learning prediction engine learns your style instead of using one fixed formula. It shows a supported range for your race, not a fake-exact number, and the training paces to get you there.

This is what makes PIRX different. Strava tells you what you did. Garmin shows your data. PIRX tells you why it happened and what's next — with validated prediction accuracy of 98% across PIRX users.

New here? Start with the complete guide to predicting your race time. Want to see your time at every distance? Read race equivalency explained. Wondering if your goal fits your training? Check is my goal time realistic. When you are ready, get your paces below.

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Race Time Predictor

Sources

Seiler, S. (2010). What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance. (The ~80/20 easy-to-hard split.)
Helgerud, J. et al. (2007). Aerobic high-intensity intervals improve VO2max more than moderate training. Medicine & Science in Sports & Exercise.
Runner's World (2024). What is a tempo run? (Threshold = the hardest effort where your body still clears lactate as fast as it builds it.)
The Running Channel (2024). 9 signs you're running your easy runs too fast.