Heart Rate Zones Calculator (Karvonen)
Heart-rate training zones calculator using the Karvonen heart-rate-reserve method (1957) with your own resting HR and a Tanaka 2001 age-predicted maximum or your tested figure. Training guidance, not medical advice.
Heart Rate Zones
5 Karvonen training zones
| Zone + purpose | % HRR | Range |
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How to use the HR zones calculator
Find your resting heart rate
Measure your RHR first thing in the morning before getting up, lying still for 1-2 minutes. Use a fitness tracker, smartwatch, or a finger-on-wrist count for 60 seconds, and average several mornings. Endurance-trained adults commonly sit well below the general-population range; whatever yours is, it moves every zone boundary, which is why this tool asks for it rather than assuming one.
Enter age
Age in years. The calculator uses Tanaka 2001 (208 − 0.7 × age; J Am Coll Cardiol 2001;37(1):153-156) by default. To override with your tested max HR from a field test or treadmill stress test, enter it in the override field.
(Optional) Override max HR with tested value
If you've done a max-effort field test (1-mile all-out run, treadmill ramp test, or sprint test) and observed a higher peak HR than Tanaka predicts, enter it. Otherwise leave at 0 and Tanaka 2001 is used.
Read the 5 zones
Z1 (50-60%): recovery + warm-up. Z2 (60-70%): aerobic base — most weekly miles. Z3 (70-80%): tempo / marathon pace. Z4 (80-90%): lactate threshold / 10K pace. Z5 (90-100%): VO2 max intervals.
Apply polarised training
Seiler's 2010 review of elite endurance practice (Int J Sports Physiol Perform 2010;5(3):276-291) describes a polarised pattern: most sessions clearly easy, a minority clearly hard, little in between. Use the zone table to keep the easy days genuinely easy — the failure mode it protects against is drifting into Zone 3 on every run.
Karvonen zones — using YOUR baseline, not a generic chart
Most gym wall charts give heart rate zones as percentages of "220 minus age". That is a percentage-of-maximum method — easy to compute, but blind to the reader's own baseline. A 40-year-old endurance athlete with a resting HR of 45 and a 40-year-old office worker with a resting HR of 85 share the same predicted maximum (180 by Tanaka 2001), yet their zones should differ: on the reserve method the athlete's Zone 2 is 126–140 bpm and the office worker's is 142–152 bpm. The heart-rate-reserve method captures this. It comes from a 1957 longitudinal training study by the Finnish physiologist Martti Karvonen and colleagues (Ann Med Exp Biol Fenn 1957;35(3):307-315), which expressed training intensity as a fraction of the gap between resting and maximum heart rate.
The HRR formula
Karvonen: Target HR = RHR + (MaxHR − RHR) × intensity%. Example: 40-year-old, MaxHR 180 (Tanaka), RHR 60. HRR = 120. Zone 2 (60-70%): RHR + 0.60 × 120 to RHR + 0.70 × 120 = 132 to 144 bpm. Compare to the percentage-of-max-HR method (60-70% of 180): 108-126 bpm — much lower. The HRR method better captures the working-heart-rate range. Both methods are in wide use, and ACSM's exercise-prescription guidance classifies intensity in either; the reserve method is the one that responds to your own resting figure, so it is only as good as that measurement.
Karvonen's 1957 study expressed training intensity as a fraction of the gap between resting and maximum heart rate, and is usually summarised as finding a training effect only once that fraction reached about 60% — the origin of the idea that the reserve, not the raw beat count, is what matters.
The 5-zone system + polarised training
The five-zone ladder used here — 50–60, 60–70, 70–80, 80–90 and 90–100% of heart-rate reserve — is a coaching convention, not a clinical standard. ACSM's position stand on exercise prescription classifies 40–59% of reserve as moderate and 60–89% as vigorous intensity (Garber et al., Med Sci Sports Exerc 2011;43(7):1334-1359), so this tool's Zone 2 sits at the top of ACSM's moderate band and Zones 3–4 span its vigorous band. Zone 1 is recovery and warm-up; Zone 2 is the conversational aerobic work most weekly volume is built from; Zone 3 is sustained hard effort; Zone 4 sits around lactate threshold; Zone 5 is short high-intensity intervals. Polarised training (Seiler 2010) is the observation that elite endurance athletes spend most of their sessions clearly in the easy zones and a minority clearly hard, with little in the middle.
ASEAN heat + heart rate
Heart rate at a given pace runs higher in heat and humidity — the body diverts blood to the skin to shed heat, and dehydration over a long session raises it further (a pattern ACSM's fluid-replacement position stand describes; Sawka et al., Med Sci Sports Exerc 2007;39(2):377-390). For a Singapore, Kuala Lumpur or Bangkok runner this means the same Zone 2 heart rate arrives at a slower pace than it would in a cool climate. Either slow down to hold the zone, or accept that the zone table describes effort, not pace. Repeated training in heat produces acclimatisation that partly narrows the gap.
Karvonen's reserve method, the five-zone ladder and what moves your zones
Karvonen, Kentala and Mustala (1957) expressed training intensity as a fraction of the resting-to-maximum gap — the heart-rate reserve.
HRR = Max HR − Resting HR. Wider HRR = more zone resolution.
5 zones at 10-point steps from 50% to 100% of reserve — a coaching convention; ACSM classifies 40–59% moderate and 60–89% vigorous.
Polarised training (Seiler 2010): elite endurance athletes do most sessions clearly easy and a minority clearly hard, with little in between.
Tanaka 2001 (208 − 0.7 × age), the default maximum here, came from a meta-analysis of 351 studies plus a laboratory sample of 514 adults.
Karvonen's 1957 result is usually summarised as a training threshold near 60% of the reserve — the origin of the Zone 2 floor; the paper predates online archives, so this page quotes it as reported in later reviews.
Heat raises heart rate at a given pace (ACSM 2007): in tropical conditions the same zone arrives at a slower pace.
Poor sleep, illness and dehydration raise resting HR, and every zone boundary here is computed from that figure — re-measure it rather than reusing an old one.
The two methods differ most at the bottom: for max 180 and resting 60, the Zone 2 floor is 132 bpm by reserve and 108 bpm by percent-of-max.
"Talk test" cross-check: Z2 = full sentences possible. Z3 = phrases. Z4-5 = single words gasped.
Frequently asked questions
First thing in the morning, lying still for a minute or two before getting up. Use a fitness tracker or count your pulse at the wrist or neck for 60 seconds. Repeat over several mornings and average — a single reading after a poor night's sleep will shift every zone in the table.
They answer different questions. Percent-of-max ignores your resting rate; the reserve (Karvonen) method scales the zone to the gap between resting and maximum, so it responds to your own baseline. For max 180 and resting 60 the Zone 2 floor is 132 bpm by reserve and 108 by percent-of-max — 24 bpm apart. ACSM's prescription guidance is written in either; the reserve method is only as good as your resting-HR measurement.
Because it is where most endurance volume is done. Seiler's 2010 review of elite endurance training found the bulk of sessions performed clearly below threshold, with a minority clearly above it. Zone 2 here corresponds to the top of ACSM's moderate-intensity band (40–59% of reserve). The practical failure is not too little Zone 2 but letting easy days drift into Zone 3.
Three possibilities. (1) Your true maximum is higher than the Tanaka estimate — enter a tested figure in the override field. (2) You are training in heat, which raises heart rate at a given pace; slow down to hold the zone. (3) Your resting HR is higher than entered — re-measure. Illness, dehydration and poor sleep all elevate heart rate. Use perceived exertion as a cross-check.
A training-intensity distribution described by Stephen Seiler (Int J Sports Physiol Perform 2010;5(3):276-291): most sessions clearly easy (Zones 1–2 here), a minority clearly hard (Zones 4–5), and little time in between. It describes how elite endurance athletes were observed to train; it is a distribution of sessions, not a prescription for every individual.
Poor sleep, stress and illness raise resting heart rate, and every boundary in this table is computed from the resting figure you enter. A stale or inflated resting HR narrows the reserve and shifts the zones. Re-measure on the day, and on a poor-sleep day treat the table as approximate.
Use both. The talk test is coarse but immune to monitor error and heat: full sentences at Zone 2, phrases at Zone 3, single words at Zones 4–5. If the monitor says Zone 2 and you cannot speak comfortably, trust the talk test.
No. All inputs stay in your browser.
Heart rate at a given effort is often somewhat lower on the bike than running, because less muscle mass is recruited, and maximum heart rate can differ by sport. Athletes who test in both sports sometimes keep separate maximums and zones. For recreational use the same table is a reasonable starting point.
Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn 1957;35(3):307-315. Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol 2001;37(1):153-156. Garber CE, et al. ACSM position stand: quantity and quality of exercise. Med Sci Sports Exerc 2011;43(7):1334-1359. Seiler S. Int J Sports Physiol Perform 2010;5(3):276-291.
Method & sources
How it computes
Five training zones by the Karvonen heart-rate-reserve method: target = resting HR + (max HR − resting HR) × intensity, at 50–60, 60–70, 70–80, 80–90 and 90–100% of reserve. Maximum HR is the reader's tested figure (80–230 bpm accepted) or, by default, Tanaka's 208 − 0.7 × age. Training guidance, not medical advice.
What this tool implements
- Karvonen (1957) heart-rate-reserve method; percent-of-max is a different method and is not what this page prints
- Tanaka, Monahan & Seals (2001) 208 − 0.7 × age as the default age-predicted maximum, for ages 10–100; a typed override must be 80–230 bpm
- Five-zone ladder at 10-point steps from 50% to 100% of reserve — a coaching convention, mapped on the page to ACSM's moderate (40–59% HRR) and vigorous (60–89% HRR) bands (Garber et al. 2011)
- Resting HR accepted 30–120 bpm; a resting HR at or above the maximum yields no ladder and a named warning rather than an inverted table
Sources
- Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn 1957;35(3):307-315.
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol 2001;37(1):153-156.
- Garber CE, Blissmer B, Deschenes MR, et al. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults. Med Sci Sports Exerc 2011;43(7):1334-1359.
- Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? Int J Sports Physiol Perform 2010;5(3):276-291.
What can make this go out of date
- None at runtime — the Karvonen and Tanaka equations are fixed published formulas.
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