Phase 6 · Biometric & Longevity
Heart Rate Zone Calculator
Most people train in the grey zone: too hard to be easy, too easy to be hard. Get your five zones in real bpm — from your own heart rate reserve, not a generic wall chart.
Educational estimate — not medical advice. Age-predicted max heart rate is a population average with wide individual variation, and medications such as beta-blockers can change your heart rate response entirely. Consult a physician before strenuous exercise or maximal testing, especially if you're older, new to training, or have any heart or health condition.
How do you calculate your heart rate training zones?
Take your maximum heart rate — measured, or estimated as 220 − age or Tanaka's 208 − 0.7 × age — and subtract your resting heart rate to get your heart rate reserve. Each zone is then your resting rate plus a share of that reserve: 50–60% for Zone 1, then 60–70%, 70–80%, 80–90% and 90–100% for Zones 2 through 5. That is the Karvonen method.
- Heart rate reserve (HRR) = max heart rate − resting heart rate. It is the usable span your training zones are carved out of.
- Karvonen target = resting HR + (HRR × intensity%). The simpler %MaxHR target is just max HR × intensity%, which lands lower in bpm.
- The classic 220 − age formula carries a standard deviation of about ±10–12 bpm between individuals — a measured max from a lab or supervised field test is far more accurate.
- Tanaka et al. (2001) proposed 208 − 0.7 × age from a meta-analysis of 351 studies and a laboratory sample of 514 healthy adults; it tracks older adults better. The two equations agree exactly at age 40.
Under the hood
The formulas, fully cited
Two age-predicted max heart rate equations, one reserve calculation, and two ways of turning an intensity percentage into bpm:
Max HR (classic) = 220 − age
Max HR (Tanaka et al., 2001) = 208 − 0.7 × age
Heart rate reserve (HRR) = HRmax − HRresting
Karvonen target HR = HRresting + (HRR × intensity%)
%MaxHR target HR = HRmax × intensity%
Zones (% of HRR) — Z1 50–60% · Z2 60–70% · Z3 70–80% · Z4 80–90% · Z5 90–100%
- Why Karvonen is the headline: it works off the span between your resting and max heart rate, so a fit person with a resting pulse of 45 and an untrained person at 75 get genuinely different zones from the same max. The %MaxHR row is shown alongside because it is what most published charts use — and it always lands lower in bpm.
- The estimates have real error bars: age-predicted max heart rate has an individual standard deviation of roughly ±10–12 bpm. Tanaka et al. showed the classic 220 − age formula overestimates max HR in the young and underestimates it in older adults; the two equations cross at exactly age 40 and diverge by 0.3 bpm for every year either side. If you have a measured max, use it — that is what the "Measured" option is for.
- Zone boundaries are conventions, not physiology: the 50/60/70/80/90% bands are a widely used five-zone scheme, but your real lactate threshold and VO2 max intensities sit where your body puts them. Lab testing (lactate or gas exchange) is the only way to place them exactly.
- Things that shift your heart rate on the day: heat, humidity, altitude, dehydration, caffeine, illness, poor sleep and cardiac drift late in long sessions. Beta-blockers and some other medications lower both resting and max heart rate, which invalidates age-predicted zones entirely.
- Guarded math: if your resting heart rate is entered at or above your max, heart rate reserve would be zero or negative — the tool floors it and flags the inputs rather than printing nonsense.
Your directives
What to do next, based on your numbers
Adjust the sliders to generate tailored recommendations.
Answers
Frequently asked questions
How do I calculate my heart rate training zones?
Start with your maximum heart rate — either measured, or estimated as 220 − age (classic) or 208 − 0.7 × age (Tanaka). Subtract your resting heart rate to get your heart rate reserve (HRR). Then each zone is your resting heart rate plus a percentage of that reserve: Zone 1 is 50–60%, Zone 2 is 60–70%, Zone 3 is 70–80%, Zone 4 is 80–90% and Zone 5 is 90–100%. That is the Karvonen method, and it is what this calculator uses for its headline numbers.
Karvonen vs %MaxHR — which method should I use?
The %MaxHR method just takes a percentage of your max heart rate, ignoring how low your resting rate is. Karvonen works off your heart rate reserve — the usable span between resting and max — so it adapts to your own physiology. Because Karvonen adds the percentage on top of your resting rate, its zones sit higher in bpm than the same percentage of max, and the gap widens the lower your resting heart rate is. Karvonen is generally the better guide for trained athletes with a low resting pulse; %MaxHR is simpler and is what most gym charts print. This tool shows both so you can see the difference on your own numbers.
How accurate is 220 − age?
Not very, for any one person. It is a population average with a standard deviation of roughly ±10–12 bpm between individuals, so two healthy 40-year-olds can genuinely differ by 20+ bpm at max. It also has a known age bias: Tanaka et al. found it overestimates max heart rate in young adults and underestimates it in older adults. The two equations cross at age 40 — below that, 220 − age reads higher; above it, Tanaka reads higher, and the gap grows about 0.3 bpm per year. A measured max from a lab test or a supervised all-out effort beats both.
What is Zone 2 and why does everyone talk about it?
Zone 2 is the easy aerobic band — 60–70% of heart rate reserve — the intensity where you could hold a conversation. It is the zone that builds the aerobic base: capillary density, mitochondrial function and fat oxidation. The reason coaches push it is volume: you can accumulate hours there each week without the recovery cost of hard work, which is exactly what a bigger aerobic engine requires. Most endurance programs put the large majority of weekly time at or below Zone 2 and reserve a small slice for Zone 4–5 work.
How do I find my actual maximum heart rate?
A graded exercise test in a lab or clinic is the gold standard. The practical alternative is a supervised maximal field test — for example, a thorough warm-up followed by repeated hard efforts up a hill, with the highest number your chest strap records taken as your max. Both are genuinely maximal efforts, so get medical clearance first if you are older, new to intense exercise or have any cardiovascular risk. Note that a wrist optical sensor often under-reads at high intensity; a chest strap is far more reliable for this.