| Zone | Intensity | Heart rate (bpm) | Purpose |
|---|
How heart rate training zones work
Heart rate zones translate a percentage of your maximum heart rate into a target range of beats per minute, so you can train at the right intensity instead of guessing. Most endurance coaches use a five-zone model, from easy recovery (Zone 1) to maximal VO2 max efforts (Zone 5).
This calculator estimates your maximum heart rate from your age, then works out the bpm range for each zone. If you know your resting heart rate, switch to the Karvonen method for a more personalised result — and if you have a lab- or field-tested max heart rate, enter it directly.
The five heart rate zones explained
Zone 1 — Recovery (50–60%)
Very easy effort for warm-ups, cool-downs, and recovery runs. You should be able to hold a full conversation.
Zone 2 — Easy / aerobic base (60–70%)
The bread and butter of endurance training. Zone 2 builds aerobic capacity and fat metabolism. Most of your weekly mileage should live here, even though it feels almost too easy.
Zone 3 — Aerobic / tempo (70–80%)
"Comfortably hard." Useful in moderation, but many runners spend too much time here — the grey zone that is too hard to recover from and too easy to drive big gains.
Zone 4 — Threshold (80–90%)
Around your lactate threshold — the fastest pace you can sustain for roughly an hour. Threshold work raises the ceiling on your sustainable race pace.
Zone 5 — VO2 max (90–100%)
Maximal aerobic efforts done as short intervals. Zone 5 develops top-end power and running economy but is demanding, so it is used sparingly.
%HRmax vs the Karvonen method
The %HRmax method takes flat percentages of your maximum heart rate. It is simple and only needs your age, but it ignores how fit you are.
The Karvonen method uses your heart rate reserve — the gap between your maximum and resting heart rate — with the formula: target = resting HR + intensity% × (max HR − resting HR). Because a fitter runner has a lower resting heart rate, Karvonen produces higher, more realistic easy-run targets for trained athletes. If you know your resting heart rate, it is usually the better choice.
Maximum heart rate by age (Tanaka estimate)
These are estimated maximum heart rates and the Zone 2 easy-run range using the Tanaka formula (208 − 0.7 × age). Individual maximums vary by 10–15 bpm, so treat these as a starting point, not gospel.
| Age | Estimated max HR | Zone 2 (60–70%) | Zone 4 (80–90%) |
|---|---|---|---|
| 20 | 194 | 116–136 | 155–175 |
| 30 | 187 | 112–131 | 150–168 |
| 40 | 180 | 108–126 | 144–162 |
| 50 | 173 | 104–121 | 138–156 |
| 60 | 166 | 100–116 | 133–149 |
Zones from your real runs, not a formula
Age-based formulas are estimates. The Running Genie sets your zones from your actual heart rate data and race efforts — and builds a plan that keeps most of your running in the right zone.
Frequently asked questions
How do I calculate my heart rate zones?
First estimate your maximum heart rate — the Tanaka formula (208 − 0.7 × age) is more accurate than the old 220 − age. Then take percentages for each zone: Zone 1 is 50–60%, Zone 2 is 60–70%, Zone 3 is 70–80%, Zone 4 is 80–90%, Zone 5 is 90–100%. The Karvonen method refines this using your heart rate reserve (max minus resting).
What is the Karvonen formula?
The Karvonen method calculates target heart rate from your heart rate reserve: target = resting HR + intensity% × (max HR − resting HR). Because it accounts for your resting heart rate, it personalises zones better than a flat percentage of max — especially for fitter runners with a low resting pulse.
What is Zone 2 heart rate and why does it matter?
Zone 2 is roughly 60–70% of your maximum heart rate — an easy, conversational effort. It builds aerobic base, improves fat metabolism, and should make up the majority of most runners' weekly mileage. Training too hard on easy days is the most common mistake amateur runners make.
Should I use %HRmax or the Karvonen method?
%HRmax is simpler and only needs your age. Karvonen is more personalised because it uses your resting heart rate, which reflects your fitness. If you know your resting heart rate, Karvonen usually gives more realistic easy-run zones. If you only know your age, %HRmax is fine to start.
How do I find my maximum heart rate?
The most accurate way is a supervised max-HR field test — for example, a hard progressive run finishing with an all-out effort up a hill. Formulas like Tanaka are good estimates but can be off by 10–15 bpm for any individual. If you have a measured max, enter it directly in the calculator.
How do I measure my resting heart rate?
Measure it first thing in the morning before getting out of bed, lying still, counting beats for 60 seconds. Do it across several days and average them. A typical resting heart rate is 60–100 bpm; endurance-trained runners are often in the 40s or 50s.
Related running calculators
Train in the right zone, automatically
Download The Running Genie to set your zones from real heart rate data and get a plan that keeps your easy days easy and your hard days hard.
