Tool · Physiology
Running training zones calculator
From your maximal aerobic speed (MAS), get your 7 training zones with the pace in min/mi for each one, from recovery to intervals. Add your max and resting heart rate to see the target heart rate for every zone, calculated with the Karvonen method.
| Zone | % MAS | Pace | Target HR |
|---|---|---|---|
| Z1 · Active recovery | 50 to 60% | 10:06 to 12:07 /mi | 123 to 136 bpm |
| Z2 · Easy aerobic | 60 to 70% | 8:40 to 10:06 /mi | 136 to 150 bpm |
| Z3 · Tempo / steady | 70 to 80% | 7:34 to 8:40 /mi | 150 to 163 bpm |
| Z4 · Anaerobic threshold | 80 to 90% | 6:44 to 7:34 /mi | 163 to 177 bpm |
| Z5 · MAS / VO₂max | 90 to 105% | 5:46 to 6:44 /mi | 177 to 190 bpm |
| Z6 · Anaerobic capacity | 105 to 120% | 5:03 to 5:46 /mi | 190 bpm |
| Z7 · Max neuromuscular power | 120 to 150% | 4:02 to 5:03 /mi | 190 bpm |
Paces are derived from your MAS (zones from 50% to 150% of MAS). Target heart rates use the Karvonen method on your heart-rate reserve (max HR 190 bpm, resting HR 55 bpm), with the zone’s % of MAS as the intensity. Above MAS, heart rate tops out at your max. These are training guidelines, not medical advice.
How the zones are calculated
A training zone is an intensity range. It’s usually defined as a percentage of your maximal aerobic speed (MAS, or vVO₂max), then turned into a pace. RunMorph uses 7 zones, from recovery (50 to 60% of MAS) up to neuromuscular power (above 120%).
1. From MAS to pace
For a given zone, work out the speed that matches its percentage of MAS, then turn that speed into a pace:
pace (min/mi) = 60 ÷ speed (mph)
Example for a MAS of 10 mph, in the easy aerobic zone (60 to 70%): the zone runs from 10 × 0.60 = 6 mph to 10 × 0.70 = 7 mph, so a pace from 60 ÷ 7 = 8:34/mi (fast end) to 60 ÷ 6 = 10:00/mi (slow end).
2. From zone to heart rate (Karvonen)
If you enter your max and resting heart rates, the tool adds the target heart rate for each zone with the Karvonen method, based on your heart-rate reserve (the gap between the two):
target HR = resting HR + intensity × (max HR minus resting HR)
The intensity used is the zone’s percentage of MAS (capped at 100%: above MAS, heart rate tops out at your max).
Example with a max HR of 190 bpm and a resting HR of 55 bpm (reserve = 135 bpm), in the easy aerobic zone at 65% intensity: target HR = 55 + 0.65 × 135 = 55 + 87.75 ≈ 143 bpm.
The 7 zones: benchmarks as % of MAS
What each zone is for and the percentage of MAS it matches. The calculator above turns these ranges into paces (and target heart rates) for your own MAS.
| Zone | Name | % MAS | What it’s for |
|---|---|---|---|
| Z1 | Active recovery | 50 to 60% | Shaking out the legs, very easy jogs between two hard sessions. |
| Z2 | Easy aerobic | 60 to 70% | The bulk of your mileage: easy runs and relaxed long runs. |
| Z3 | Tempo / steady | 70 to 80% | Marathon pace, sustained aerobic running. |
| Z4 | Anaerobic threshold | 80 to 90% | Half marathon to 10K pace, threshold work. |
| Z5 | MAS / VO₂max | 90 to 105% | Short intervals, VO₂max sessions. |
| Z6 | Anaerobic capacity | 105 to 120% | Very hard, very short repeats, tolerance to acidity. |
| Z7 | Neuromuscular power | 120 to 150% | Short sprints, strides, explosiveness. |
These percentages are benchmarks. Most of your mileage happens in Z1 and Z2 (endurance), quality work is concentrated in Z4 and Z5, 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 maximal aerobic speed, then that percentage is turned into a pace. Common benchmarks: recovery at 50 to 60% of MAS, easy aerobic running at 60 to 70%, marathon pace (tempo) at 70 to 80%, threshold at 80 to 90%, MAS and intervals at 90 to 105%, then very short work beyond that. 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 + intensity × (max HR minus resting HR). It’s more personal than a simple percentage of max HR because it accounts for your heart at rest. In this tool, each zone’s intensity is its percentage of MAS.
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. The link between % of MAS and % of heart-rate reserve isn’t strictly linear from one runner to the next, and heart rate drifts with fatigue, heat or dehydration. 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, 220 minus your age gives a ballpark figure, often off by several beats. Measure your resting HR on waking, lying down, before you get up.
Turn your zones into a training plan
RunMorph calculates your zones from your maximal aerobic speed and builds a session-by-session plan, periodized all the way to race day, with the right pace for every run.
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