Tool · Physiology
Running training zones calculator
From your maximal aerobic speed (MAS), get your 7 pace zones with the pace in min/mi for each one, from recovery to sprint. Add your max and resting heart rate to see the heart-rate zone that goes with each pace, calculated with the Karvonen method.
| Pace zone | % MAS | Pace | Heart-rate zone |
|---|---|---|---|
| Z1 · Recovery | 55 to 65% | 9:19 to 11:01 /mi | Z1 · 123 to 136 bpm |
| Z2 · Easy endurance | 65 to 75% | 8:05 to 9:19 /mi | Z2 · 136 to 150 bpm |
| Z3 · Tempo / marathon pace | 76 to 83% | 7:18 to 7:58 /mi | Z3 · 150 to 163 bpm |
| Z4 · Threshold | 84 to 92% | 6:35 to 7:13 /mi | Z4 · 163 to 177 bpm |
| Z5 · MAS | 95 to 100% | 6:04 to 6:23 /mi | Z5 · 177 to 190 bpm |
| Z6 · Anaerobic capacity | 102 to 110% | 5:31 to 5:57 /mi | HR not relevant: go by pace |
| Z7 · Speed / sprint | over 110% | faster than 5:31 /mi | HR not relevant: go by pace |
Paces are calculated as a percentage of your field MAS, with the same table as RunMorph plans (Z1 to Z7). Heart-rate zones use the Karvonen method, as a percentage of your heart-rate reserve (max HR 190 bpm, resting HR 55 bpm): Z1 50-60%, Z2 60-70%, Z3 70-80%, Z4 80-90%, Z5 90-100%. Zones Z6 and Z7 are too short for heart rate to be a useful guide. These are training guidelines, not medical advice.
How the zones are calculated
A training zone is an intensity range. Pace zones are defined as a percentage of your field maximal aerobic speed (MAS, the speed you can hold for about 6 minutes all-out), then turned into a pace. RunMorph uses a single table of 7 pace zones, from recovery (55 to 65% of MAS) up to speed (above 110%), and 5 heart-rate zones.
1. From MAS to pace
For a given zone, work out the speeds that match its bounds as a percentage of MAS, then turn them into paces:
pace (min/mi) = 60 ÷ speed (mph)
Example for a MAS of 10 mph, in the easy endurance zone (65 to 75%): the zone runs from 10 × 0.65 = 6.5 mph to 10 × 0.75 = 7.5 mph, so a pace from 60 ÷ 7.5 = 8:00/mi (fast end) to 60 ÷ 6.5 = 9:14/mi (slow end).
2. Heart-rate zones (Karvonen)
If you enter your max and resting heart rates, the tool adds the heart-rate zone of each pace zone, calculated with the Karvonen method on your heart-rate reserve (the gap between the two):
target HR = resting HR + % × (max HR minus resting HR)
Heart-rate zones run from 50-60% of reserve (Z1) to 90-100% (Z5). Pace zone Z2 matches heart-rate zone Z2, and so on up to Z5. Pace zones Z6 and Z7 have no heart-rate zone: on such short efforts, heart rate doesn’t have time to rise, so go by pace.
Example with a max HR of 190 bpm and a resting HR of 55 bpm (reserve = 135 bpm), in heart-rate zone Z2 (60 to 70% of reserve): from 55 + 0.60 × 135 = 136 bpm to 55 + 0.70 × 135 ≈ 150 bpm.
The 7 zones: benchmarks as % of MAS
What each pace zone is for, the percentage of MAS it matches and the heart-rate zone that goes with it. The calculator above turns these ranges into paces (and heart rates) for your own MAS.
| Pace zone | Name | % MAS | Heart-rate zone | What it’s for |
|---|---|---|---|---|
| Z1 | Recovery | 55 to 65% | Z1 (50-60% of HR reserve) | Shaking out the legs, warm-ups, very easy jogs between two hard sessions. |
| Z2 | Easy endurance | 65 to 75% | Z2 (60-70% of HR reserve) | The bulk of your mileage: easy runs and relaxed long runs. |
| Z3 | Tempo / marathon pace | 76 to 83% | Z3 (70-80% of HR reserve) | Marathon pace, sustained aerobic running. |
| Z4 | Threshold | 84 to 92% | Z4 (80-90% of HR reserve) | Half marathon to 10K pace, threshold work (the pace you hold for about 1 hour is about 86% of MAS). |
| Z5 | MAS | 95 to 100% | Z5 (90-100% of HR reserve) | MAS sessions: repeats of 3 to 6 minutes. |
| Z6 | Anaerobic capacity | 102 to 110% | HR not relevant: go by pace | Short, hard repeats of 30 seconds to 2 minutes. |
| Z7 | Speed / sprint | over 110% | HR not relevant: go by pace | Sprints under 30 seconds, strides, explosiveness. |
These percentages are benchmarks. Most of your mileage happens in Z1 and Z2 (endurance), quality work is spread across Z3, Z4 and Z5 depending on your race, and the top zones stay reserved for very short efforts.
Frequently asked questions
How do I calculate my training zones from my MAS?
Each zone is expressed as a percentage of your field maximal aerobic speed, then that percentage is turned into a pace. RunMorph’s table: recovery at 55 to 65% of MAS, easy endurance at 65 to 75%, tempo and marathon pace at 76 to 83%, threshold at 84 to 92%, MAS at 95 to 100%, anaerobic capacity at 102 to 110%, speed above 110%. The calculator applies these ranges to your MAS and shows the pace in min/mi for each of the 7 zones.
What is the Karvonen method for heart rate?
Karvonen calculates a target heart rate from your heart-rate reserve, the gap between your max HR and your resting HR. The formula is: target HR = resting HR + % × (max HR minus resting HR). It’s more personal than a simple percentage of max HR because it accounts for your heart at rest. RunMorph’s 5 heart-rate zones run from 50-60% of reserve (Z1) to 90-100% (Z5); each pace zone Z1 to Z5 has the heart-rate zone with the same number.
Should I train by pace or by heart rate?
Both are useful and complement each other. Pace (min/mi) is precise and responds instantly, ideal for nailing intervals. Heart rate reflects your real internal load (heat, fatigue, hills) but lags behind and drifts on long efforts. Many runners control pace during workouts and keep an eye on heart rate during easy runs. The table’s two columns give you both benchmarks.
Why don’t my pace zones and heart-rate zones always line up?
Because they measure different things: pace is an external intensity, heart rate an internal response. On average, a pace zone matches the heart-rate zone with the same number, within half a zone, but heart rate drifts with fatigue, heat or dehydration, and it doesn’t have time to rise on very short efforts (Z6 and Z7, where only pace counts). The values in this tool are starting points: adjust them to how you feel and to your real-world data.
How do I find my MAS and max heart rate to use the tool?
For your MAS: use a recent race time, a half-Cooper test (6 minutes) or a stage test, with our dedicated MAS calculator. For max HR: a field test (all-out hill repeats) is the most reliable; failing that, the Tanaka formula (208 minus 0.7 × age) gives a ballpark figure, often off by several beats. Measure your resting HR on waking, lying down, before you get up; without it, the tool uses 55 bpm.
Turn your zones into a training plan
RunMorph calculates your zones from your field maximal aerobic speed and builds a session-by-session plan, periodized all the way to race day, with the right pace for every run.
Create my free planFree · No credit card · First 3 weeks included