Karvonen Target Heart Rate
Taking a percentage of maximum heart rate ignores how much resting rates differ between people. Karvonen works on heart-rate reserve — maximum minus resting — then adds resting back, so a fit body and an unfit one get different zones.
Your numbers
Zone low
136bpm
Zone high
154bpm
Max heart rate
185bpm
Difference
123bpm
Formula
Zone floor = (Max heart rate − Resting HR) × Percentage ÷ 100 + Resting HR
Measure resting rate the moment you wake. Taken sitting during the day it reads high and pushes the whole zone up.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| AgeAge in completed years — it shifts by one depending on the birthday. | 35 | 5 ~ 100 |
| Resting HR (bpm)Resting heart rate, taken right after waking. | 62 | 30 ~ 120 |
| Zone floor (%)The lower percentage of the target zone, applied to heart-rate reserve. | 60 | 30 ~ 100 |
| Zone ceiling (%)The upper percentage of the target zone. | 75 | 30 ~ 100 |
Step by step
Quick reference table
Results when only Age changes and everything else stays put.
| Age | Zone low (bpm) | Zone high (bpm) | Max heart rate (bpm) |
|---|---|---|---|
| 17.5 | 146 | 167 | 203 |
| 26.3 | 141 | 161 | 194 |
| 35 | 136 | 154 | 185 |
| 52.5 | 125 | 141 | 168 |
| 70 | 115 | 128 | 150 |
What each result means
| Result | At default values |
|---|---|
| Zone low (bpm)The bottom of the heart-rate band. | 136 |
| Zone high (bpm)The top of the heart-rate band. | 154 |
| Max heart rate (bpm)Maximum heart rate estimated from age; individual variation is large. | 185 |
| Difference (bpm)The gap between two values — a quantity, not a rate. | 123 |
Common mistakes
Measure resting rate the moment you wake. Taken sitting during the day it reads high and pushes the whole zone up.
Glossary
- Age
- Age in completed years — it shifts by one depending on the birthday.
- Resting HR
- Resting heart rate, taken right after waking.
- Zone floor
- The lower percentage of the target zone, applied to heart-rate reserve.
- Zone ceiling
- The upper percentage of the target zone.
- Zone low
- The bottom of the heart-rate band.
- Zone high
- The top of the heart-rate band.
- Max heart rate
- Maximum heart rate estimated from age; individual variation is large.
- Difference
- The gap between two values — a quantity, not a rate.
Frequently asked questions
Q. How is Karvonen Target Heart Rate calculated?
Zone floor = (Max heart rate − Resting HR) × Percentage ÷ 100 + Resting HR — Taking a percentage of maximum heart rate ignores how much resting rates differ between people. Karvonen works on heart-rate reserve — maximum minus resting — then adds resting back, so a fit body and an unfit one get different zones.
Q. Can you walk through an example?
With Age 35, Resting HR 62bpm, Zone floor 60%, Zone ceiling 75%, the answer is Zone low 136bpm.
Q. What do I need to enter?
Enter Age, Resting HR, Zone floor, Zone ceiling. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Age moves the answer to Age 17.5 → Zone low (bpm) 146 and Age 70 → Zone low (bpm) 115. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
Measure resting rate the moment you wake. Taken sitting during the day it reads high and pushes the whole zone up.
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These calculators help you understand health figures; they do not replace diagnosis or prescription. See a clinician if you have symptoms.