Find your maximum heart rate and target heart-rate zones for fitness training. Enter your age (and optionally your resting heart rate) - the calculator returns five training zones, from warm-up to maximum effort, using both the Tanaka and 220-age formulas.
Measure first thing in the morning before getting up.
Maximum heart rate
188 bpm
208 − 0.7 × age
Heart rate reserve
118 bpm
Max 188 − Rest 70
Target zones (Karvonen)
Predicted max HR is an estimate. Real max varies by ±10–15 bpm. For exact testing, use a graded exercise test under medical supervision. Stop and consult a doctor if you experience chest pain, dizziness, or unusual symptoms during exercise.
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Heart rate training transformed endurance sports in the 1980s-90s and has become mainstream with the rise of fitness wearables. Knowing your maximum heart rate and personalised training zones lets you train smart - pushing hard enough to improve, but not so hard that you injure yourself or burn out. This calculator uses both the modern Tanaka formula (most accurate for the general population) and the classic 220-age (still widely used and useful as a quick reference), then applies the Karvonen method to derive five target zones personalised by your resting heart rate.
The Karvonen method, used by sports cardiologists since the 1957 original paper, computes target zones based on Heart Rate Reserve (HRR) - the gap between resting and max HR. This produces zones that are more individualised than simple percent-of-max-HR. A fit person with resting HR 50 has a much larger HRR than a sedentary person with resting HR 80, even at the same age. The Karvonen zones reflect this, giving meaningfully different target HRs for the same exercise intensity.
Enter your age in years.
Enter your resting heart rate. Measure it in the morning before getting out of bed.
Pick a max-HR formula - Tanaka (more accurate) or 220-age (classic).
View your max HR and target zones in beats per minute.
Use the zones during cardio: warm-up, fat burn, aerobic, anaerobic, or maximum effort.
Maximum heart rate (MHR) is the upper limit of how fast your heart can beat. Training zones are percentages of your heart rate reserve (max minus resting). The Karvonen formula uses HR reserve to give zones that are personalised to your fitness level - more useful than zones based on max HR alone.
Tanaka: Max HR = 208 − 0.7 × age 220-age: Max HR = 220 − age Karvonen: Target = (Max − Rest) × Intensity + Rest
Max HR formulas: Tanaka (208 − 0.7 × age) is more accurate for adults across age groups, validated across many population studies since 2001. 220-age (the classic) is simpler but tends to underestimate max HR in adults over 40 and overestimate in young adults. Both are population averages - individual variation is ±10-15 bpm - so consider both as estimates. The most accurate way to find true max HR is a graded exercise test (treadmill ramp) under medical supervision, which most people don't need.
Karvonen target HR = (Max HR − Resting HR) × Intensity + Resting HR. Standard zones: Zone 1 (warm-up, 50-60% HRR), Zone 2 (fat burn / aerobic base, 60-70% HRR), Zone 3 (aerobic / cardio, 70-80% HRR), Zone 4 (anaerobic / threshold, 80-90% HRR), Zone 5 (maximum effort, 90-100% HRR). Most fitness improvement happens at Zone 2 (long duration aerobic base) and Zone 4 (interval threshold work). Zone 1 and 5 are limited to warm-up/cooldown and short bursts.
Measure resting heart rate properly. Take it in the morning before getting out of bed, ideally for 60 seconds, three days in a row, and average. Wearables work too - most smartwatches report resting HR automatically based on overnight measurements. Normal adults: 60-100 bpm. Trained endurance athletes: 40-60 bpm (lower is better, indicating cardiac efficiency). Consistently above 90 bpm at rest in healthy adults can indicate stress, dehydration, illness or - if persistent - needs medical evaluation.
Tanaka max HR = 208 − 0.7 × 35 = 183.5 bpm. HRR = 183.5 − 65 = 118.5 bpm. Zone 1 (50-60%): 124-136 bpm. Zone 2 (60-70%): 136-148 bpm. Zone 3 (70-80%): 148-160 bpm. Zone 4 (80-90%): 160-172 bpm. Zone 5 (90-100%): 172-184 bpm. For endurance base building, train mostly in Zone 2 (136-148 bpm); for performance gains, add Zone 4 intervals.
Tanaka max HR = 208 − 0.7 × 55 = 169.5 bpm. HRR = 99.5. Zone 2: 130-140 bpm. Note: the classic 220 − age formula gives max HR of 165 bpm, underestimating by 4-5 bpm - meaningful for older adults wanting accurate zones.
Tanaka (208 − 0.7 × age) is more accurate for adults across age groups. The classic 220 − age underestimates max HR for older adults and overestimates it for the very young. Both are population averages - individual variation is ±10–15 bpm.
Adults: 60–100 bpm. Trained athletes can have 40–60 bpm. Consistently above 90 bpm at rest may need medical evaluation, especially if combined with other symptoms.
Roughly 60–70% of HR reserve. The body uses a higher proportion of fat for fuel here, but the absolute calories burned per minute are lower than at higher intensities. For overall fat loss, total calories burned matter more than the zone.
Yes - predicted max HR is an estimate. Actual max varies by ±10–15 bpm. The most accurate way to find your true max is a graded exercise test under medical supervision.
Only briefly, in HIIT or anaerobic intervals. Sustained max-effort training is exhausting and not necessary. Most fitness improves in zones 2–3 (60–80% HR reserve).
Most smartwatches use the same formulas but may pull a different resting HR or max HR baseline. Check the watch's settings to align with this calculator.
Body composition, daily energy needs and pregnancy timelines all rest on formulas validated across millions of people, but no single number tells the whole story. The values from this calculator are point estimates with a known margin of error - body fat from skinfold or US Navy method has roughly a ±3% standard error compared to a DEXA scan, and BMR can vary ±10% person to person at the same height and weight. Use these numbers to track trends week over week, not to chase decimal precision day to day.
Pair this tool with the BMR, TDEE, calorie and macro calculators to turn a single measurement into an actionable plan. None of these tools are a substitute for a qualified doctor, registered dietitian or certified strength coach - but they remove the busywork so you spend more time on training and recovery, less on math.
The Heart Rate Calculator is part of the Health & Fitness suite on Online Calculator Tools, alongside 6 related calculators. All tools share the same UI patterns, the same privacy-first rendering (nothing is sent to a server), and the same commitment to showing the formula and assumptions behind every result.
