Calculate five heart-rate training zones with the Karvonen formula, using either the Fox or Tanaka estimate of maximum heart rate. Runs entirely in your browser — your numbers never leave this device.
| Zone | Effort | % of reserve | Target range (bpm) |
|---|---|---|---|
| Zone 1 | Very light | 50–60% | 125 – 138 |
| Zone 2 | Light | 60–70% | 138 – 151 |
| Zone 3 | Moderate | 70–80% | 151 – 164 |
| Zone 4 | Hard | 80–90% | 164 – 177 |
| Zone 5 | Maximum | 90–100% | 177 – 190 |
Informational only. This calculator applies a published formula to the numbers you enter — it is not medical advice, a diagnosis, or a substitute for a clinician. Talk to a qualified professional about decisions concerning your health.
| Zone | Intensity (% of heart-rate reserve) | Effort name |
|---|---|---|
| 1 | 50–60% | Very light |
| 2 | 60–70% | Light |
| 3 | 70–80% | Moderate |
| 4 | 80–90% | Hard |
| 5 | 90–100% | Maximum |
The Karvonen method builds training zones from heart-rate reserve — the difference between maximum and resting heart rate. Each zone boundary is the resting rate plus a percentage of that reserve: 50–60% of reserve defines zone 1, and the bands rise in 10-point steps to 90–100% for zone 5. Because the reserve starts from the individual's resting rate, two people of the same age with different resting rates get different zone boundaries from the same formula.
Maximum heart rate itself is estimated, and the page offers the two published estimates in standard use: the Fox form, 220 minus age, and the Tanaka form, 208 minus 0.7 times age, published in 2001 from a meta-analysis. The third worked example isolates the difference: for the same 30-year-old with a resting rate of 60, Tanaka gives a maximum of 187 against Fox's 190, and zone 1 shifts accordingly. Both maxima are population estimates; a measured maximum from a supervised test is a different input and can be entered where a tool accepts one.
The zone names in the table — Very light through Maximum — are the effort labels conventionally attached to the Karvonen bands, printed as the published reference table for locating a rate. The output is formula arithmetic for information only, not exercise instruction for any person.
Maximum heart rate minus resting heart rate. The Karvonen formula applies each zone percentage to the reserve and adds the resting rate back, which is why resting rate is a required input on this page.
Two published estimates of maximum heart rate. Fox uses 220 − age; Tanaka, from a 2001 meta-analysis, uses 208 − 0.7 × age. At age 30 they give 190 and 187 respectively, and the worked examples show the effect on the zones.
No. The table prints the conventional Karvonen bands and effort names as a published reference, and the calculator applies the formula to the inputs given. It does not prescribe training for any person.
Both Fox and Tanaka are population estimates, and individual measured maxima vary around them. The zone boundaries inherit that variation, which is why the page names the estimate used for every result.
No. The calculation runs entirely in the browser and nothing entered is uploaded, stored or tracked.
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