Zone 2 Heart Rate Calculator
Find your Zone 2 aerobic-base heart rate — the conversational, fat-burning, mitochondria-building zone — plus all five training zones for your age.
Est. max HR 184 bpm · %HRmax
Educational estimate, not medical advice. Formula max-HR can sit ±10–12 bpm from your true max — pair these zones with the "talk test" (full sentences = Zone 2). For precise zones use a lab or field test.
Stay in Zone 2 — automatically
ONDA Life pairs with your HR monitor and tracks time-in-zone and recovery — so your aerobic base actually compounds instead of drifting into Zone 3.
Download ONDA Life on the App Store →Sources & methodology
Max heart rate is estimated with the Tanaka equation (208 − 0.7 × age), which the original study found more accurate across adult ages than the familiar 220 − age. Zones are then taken as percentages of max HR, or — if you enter a resting HR — by the Karvonen heart-rate-reserve method, which personalises the zones to your fitness. Zone 2 is the easy, conversational aerobic band that endurance research (Seiler) shows should make up most training volume. These are population formulas: an individual’s true max HR can differ by ±10–12 bpm, so a lab or maximal field test is more precise than any age formula.
- [1] Tanaka H, Monahan KD, Seals DR (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology, 37(1):153–156.
The HRmax = 208 − 0.7 × age equation used here — more accurate across adult ages than the older 220 − age.
- [2] Karvonen MJ, Kentala E, Mustala O (1957). The effects of training on heart rate: a longitudinal study. Annales Medicinae Experimentalis et Biologiae Fenniae, 35(3):307–315.
Origin of the heart-rate-reserve (Karvonen) method used when you enter a resting HR.
- [3] Seiler S, Kjerland GØ (2006). Quantifying training intensity distribution in elite endurance athletes: is there evidence for an "optimal" distribution?. Scandinavian Journal of Medicine & Science in Sports, 16(1):49–56.
Evidence that the bulk of endurance training should sit in the easy, aerobic (Zone 2) band below the first threshold.
Common questions
Where do these heart-rate zones come from?
Max HR uses the Tanaka 2001 equation (208 − 0.7 × age), validated as more accurate than 220 − age. With a resting HR entered, zones use the Karvonen (1957) heart-rate-reserve method. The emphasis on a large Zone 2 base reflects endurance-training research such as Seiler & Kjerland (2006). Full citations are in the Sources section on this page. Note age formulas estimate max HR to within roughly ±10–12 bpm.
What is Zone 2 heart rate?
Zone 2 is the aerobic "base" zone — roughly 60–70% of your maximum heart rate, the pace at which you can still hold a conversation. It is where the body preferentially burns fat and builds mitochondrial density, which is why endurance athletes spend the bulk of their training there.
How do I calculate my Zone 2?
Estimate your max HR (this tool uses the Tanaka formula, 208 − 0.7·age, more accurate than the old 220 − age), then take 60–70% of it. If you know your resting heart rate, the Karvonen method — (maxHR − restHR)·intensity + restHR — personalises the range further.
How accurate are formula-based max-HR estimates?
They are population averages with a real spread — individual max HR can sit ±10–12 bpm from any formula. For precise zones, a lab test or an all-out field test beats a formula. For most people, the Tanaka estimate plus the "talk test" (you can speak in full sentences in Zone 2) is close enough.
How much Zone 2 should I do?
A common target is 150–180+ minutes per week, often as 3–4 sessions of 45–60 minutes, kept strictly easy. The discipline is staying IN the zone — most people drift into Zone 3, which blunts the aerobic-base adaptation. A heart-rate monitor (chest strap is most accurate) keeps you honest.
Why use Tanaka instead of 220 minus age?
220 − age is simple but systematically over-estimates max HR in younger adults and under-estimates it in older adults. The Tanaka 2001 formula (208 − 0.7·age), derived from a large meta-analysis, tracks the real age decline better. This tool shows both so you can compare.