❤ Heart Rate Calculator
Maximum heart rate, heart rate reserve and the five training zones. If you know your resting rate, the Karvonen method personalises the zones considerably better than the simple percentage-of-max approach.
Training zones, and why your maximum heart rate is probably not 220 minus your age
Almost every heart rate zone chart starts from 220 minus your age. It is easy to remember and it is not a research finding — it was a line drawn through scattered data in the 1970s and it carries a standard deviation of about 10 to 12 beats per minute. For roughly a third of people the true maximum is more than ten beats away from what the formula predicts.
220 − age · Tanaka: 208 − (0.7 × age)
| Age | 220 − age | Tanaka | Difference |
|---|---|---|---|
| 20 | 200 | 194 | −6 |
| 30 | 190 | 187 | −3 |
| 40 | 180 | 180 | 0 |
| 50 | 170 | 173 | +3 |
| 60 | 160 | 166 | +6 |
| 70 | 150 | 159 | +9 |
They agree at forty and part company in both directions, which is why the older formula systematically overestimates young athletes' maximums and underestimates those of older ones. The Tanaka equation, from a meta-analysis of over 350 studies, is the better default — but both are population averages, and neither knows anything about you.
Percentage of maximum against percentage of reserve
Two methods produce quite different zones. The simple one takes a percentage of maximum heart rate. The Karvonen method takes a percentage of heart rate reserve — the span between resting and maximum — and adds the resting rate back. Reserve is the better method, because it accounts for the fact that your heart does not start at zero.
Target = ((Max − Rest) × intensity) + Rest
| Method | Zone 2 range |
|---|---|
| 60–70% of maximum (184) | 110 – 129 bpm |
| 60–70% of reserve (124) | 134 – 146 bpm |
Twenty-four beats apart for the same stated intensity. The percentage-of-maximum version puts easy running at a pace most trained people would find closer to a brisk walk, which is a common reason people conclude zone 2 training is pointless.
What the five zones are for
| Zone | Intensity | What it trains | Feels like |
|---|---|---|---|
| 1 | 50–60% | Recovery, warm-up | Easy conversation |
| 2 | 60–70% | Aerobic base, fat oxidation | Can talk in sentences |
| 3 | 70–80% | Aerobic capacity, tempo | Short sentences only |
| 4 | 80–90% | Lactate threshold | A few words |
| 5 | 90–100% | VO₂ max, anaerobic | No talking |
Most endurance programmes put about 80% of total training time in zones 1 and 2 and the remaining 20% in zones 4 and 5, deliberately avoiding the middle. Zone 3 is hard enough to need recovery but not hard enough to drive the adaptations zone 4 and 5 work produce — a trap easy to fall into because it feels productive.
The talk test is more reliable than the numbers for most people, and it is free. If you can speak in full sentences you are in zone 2; if you can manage only a few words you are in zone 4. Heart rate lags effort by a minute or two and drifts upward during long sessions in heat, so it is a guide rather than a verdict.
Resting heart rate is the figure worth tracking
A typical adult resting rate is 60 to 100 beats per minute; trained endurance athletes are often in the 40s or 50s. The absolute number says something about fitness, but the trend says more. A resting rate measured on waking, over weeks, that drifts five or more beats above your own normal commonly indicates fatigue, illness coming on, poor sleep or alcohol — often a day or two before you feel it.
Measure it before getting out of bed, over several consecutive mornings, and use the average. A single reading taken after standing up, or after coffee, is not comparable.
When a number is worth a doctor's attention
A resting rate persistently above 100 at rest, or below 50 in someone not endurance-trained, is worth mentioning to a doctor, as is any rate accompanied by dizziness, chest discomfort, breathlessness disproportionate to the effort, or a pulse that feels irregular. Beta blockers and other medications lower both resting and maximum heart rate substantially, which makes every formula on this page inapplicable — zones under those drugs need to be set by effort or by a supervised test.
A worked example
A 36-year-old with a resting rate of 60 has a predicted maximum of 184 by the old formula and 183 by Tanaka — close, because he is near the crossover age. Reserve is 124. His zone 2 runs 134 to 146 bpm and his threshold work sits at 159 to 171. Six weeks later his resting rate has fallen to 54, so his reserve has grown to 130 and every zone has shifted: the same effort now sits at a slightly different heart rate. Recalculating after a block of training is worth doing, and pairing the zones with the pace calculator keeps the effort anchored to something external.
This rarely sits on its own: the pace calculator picks up where it stops, and the calories burned calculator answers the version of the question people ask next.
Frequently Asked Questions (FAQs)
Is 220 minus age accurate?
Only as a population average. The standard deviation is about 10 to 12 beats per minute, so for roughly a third of people the real maximum is more than ten beats away from the prediction. The Tanaka formula, 208 minus 0.7 times age, fits the data better, especially for people under 30 and over 50.
What is the Karvonen method?
A way of setting zones from heart rate reserve rather than from maximum heart rate. Subtract your resting rate from your maximum, take the percentage of that span, then add the resting rate back. It gives higher and more realistic targets than taking a straight percentage of maximum.
Which zone should I train in?
Most endurance plans put about 80% of the time in zones 1 and 2 and 20% in zones 4 and 5, with little in zone 3. Easy work builds the aerobic base with low recovery cost, and hard work drives the sharper adaptations; the middle costs recovery without delivering either.
What is a normal resting heart rate?
Between 60 and 100 beats per minute for most adults, with trained endurance athletes often in the 40s or 50s. The trend in your own figure matters more than the absolute value, so measure it on waking across several mornings and use the average.
How do I find my real maximum heart rate?
Only a maximal effort test measures it, ideally supervised if you are older or have any cardiac risk factors. A hard, properly warmed-up hill effort or a race finish will usually get within a few beats. Day-to-day training does not reach it, so the highest number on your watch from an easy week is not your maximum.
Why is my heart rate higher than normal at the same pace?
Heat, dehydration, caffeine, poor sleep, illness and accumulated fatigue all raise heart rate at a given effort, and it drifts upward during any long session. If it is elevated for several days with no obvious cause, treat it as a sign to take an easy day.
Do heart rate zones work if I take beta blockers?
No. Beta blockers lower both resting and maximum heart rate, so every age-based formula and every zone derived from one is wrong. Set intensity by perceived effort and the talk test, or ask for zones based on a supervised exercise test.