Case 1
- Age
- 40
- Resting heart rate
- 60bpm
- Maximum heart rate equation
- Tanaka — 208 − 0.7 × age
- Training zone
- Zone 3 — up to 80 %
156bpm
Open with these valuesTarget Heart Rate Calculator
156bpm
Result: 156 bpmA training zone is a range, not a single number — this shows its upper limit. The Karvonen method builds it from your heart rate reserve, so a resting pulse of 50 and one of 70 put the same zone in different places.
The numbers at a glance
Held fixed: Age 40, Maximum heart rate equation Tanaka — 208 − 0.7 × age, Training zone Zone 3 — up to 80 %.
| Resting heart rate (bpm) | Result (bpm) |
|---|---|
| 40 | 152 |
| 50 | 154 |
| 60Your value | 156 |
| 70 | 158 |
| 80 | 160 |
Worked examples
Case 2
- Age
- 25
- Resting heart rate
- 50bpm
- Maximum heart rate equation
- Tanaka — 208 − 0.7 × age
- Training zone
- Zone 2 — up to 70 %
148bpm
Open with these valuesCase 3
- Age
- 60
- Resting heart rate
- 70bpm
- Maximum heart rate equation
- Tanaka — 208 − 0.7 × age
- Training zone
- Zone 4 — up to 90 %
156bpm
Open with these valuesHow it's calculated
Karvonen: HR = rest + share × (HRmax − rest)
- StepEnter your age and your resting heart rate, measured before getting up.
- StepPick an equation for maximum heart rate — Tanaka is the current default.
- StepChoose the zone you want to train in.
- ResultRead the upper limit; the zone below it is the range to stay in.
What this number means
The number is the upper limit of one training zone, not a pulse to hold for the whole session — a zone is a range, and this is where it ends. Karvonen builds that boundary from the heart rate reserve — the gap between resting and maximum heart rate — rather than from the maximum alone. With the preset values — 40 years, a resting pulse of 60, the Tanaka equation — the maximum comes to 208 − 0.7 × 40 = 180 bpm, which leaves a reserve of 120. Zone 3 runs to 80 % of that reserve, so the limit is 60 + 0.8 × 120 = 156 bpm. Each zone adds ten percentage points: zone 2 ends at 144, zone 5 at 180, the full maximum. Change only the resting pulse to 50 and the same zone 3 limit moves to 154. Read it as the top of a band, with the range below as the place to stay; because the reserve is personal, two people of the same age with different resting pulses do not share a zone. The caveat that matters most: none of the three equations measures anything. Tanaka, Fox and Gellish are population averages with real spread around them — at 40 the first two even agree on 180 — so an individual maximum can sit well away from the estimate. A maximum from a supervised test beats any age formula.
Measure the resting pulse before getting up
The resting heart rate goes straight into the Karvonen formula: with everything else unchanged, a resting pulse of 50 instead of 60 moves the zone 3 limit from 156 to 154 bpm. Take it before getting up.
An age estimate is not a measured maximum
Each of the three equations is a population average with real spread around it. If you have a maximum from a supervised test, use that rather than the age estimate.
The number is a ceiling, not a target
A training zone is a range, and the calculator gives its upper limit. The band below that limit is where the session sits.
Commonly misread
156 bpm is the number I should hold for the whole session.
It is the upper limit of zone 3, and a zone is a range. The band below that limit is the range to stay in.
We are the same age, so we train at the same pulse.
Karvonen works from the heart rate reserve, the gap between resting and maximum. A different resting pulse puts the same zone in a different place.
220 minus age gives my actual maximum heart rate.
It is a population average with real spread around it. A maximum measured in a supervised test beats any age formula.
Questions
What does the number mean?
It is the upper limit of the zone you picked, not a single target — a zone is a range. At 40 years, a resting pulse of 60 and zone 3, the calculator gives 156 bpm.
Why does my resting pulse change the answer?
The Karvonen method works from the heart rate reserve, the gap between resting and maximum, rather than from the maximum alone. In the example above a resting pulse of 50 instead of 60 moves the limit from 156 to 154 bpm.
Which maximum heart rate formula should I pick?
They differ most at the ends of the age range and hardly at all in the middle. At 40 years Tanaka and Fox both give 180 bpm and the zone limit is identical at 156; at 25 the same zone gives 164 by Tanaka.
How accurate is a predicted maximum?
Every one of these formulas is a population average with real spread around it. A measured maximum from a supervised test beats any of them, and if you have one, use it rather than an age estimate.
Which zone corresponds to which limit?
Zone 1 is 60 % of the reserve, and each zone adds ten points to zone 5 at 100 %. In the default example that is 144 bpm for zone 2 and 180 bpm for zone 5.
Sources and last check
Information, not medical advice.