Karvonen Heart Rate Calculator

The Karvonen method bases your target heart rate on your heart rate reserve (HRR), which is your maximum heart rate minus your resting heart rate. The target for a given effort is resting HR + (HRR times the intensity). For example, at 70% intensity with a max of 190 and a resting rate of 60, the reserve is 130, so the target is 60 + (130 times 0.70), or 151 bpm.

The Karvonen method folds your resting heart rate into the math, so it adjusts for individual fitness. A fitter person with a lower resting rate gets a slightly different target than someone with the same age but a higher resting rate. A plain percent of max ignores resting rate entirely, which is why two people of the same age get the exact same zones even if their fitness differs.

Measure resting heart rate first thing in the morning, before you get up, ideally averaged over a few days. For maximum heart rate, the most accurate value comes from a supervised max-effort test or the peak reading from a hard race. If you do not have a measured value, this tool can estimate it from your age using the Fox, Tanaka, or Gulati formula.

Fox (220 minus age) is the classic and simplest estimate, but it tends to be less accurate at the extremes of age. Tanaka (208 minus 0.7 times age) is based on a large meta-analysis and is generally considered more reliable for adults. Gulati (206 minus 0.88 times age) was derived specifically for women. A measured value always beats any estimate.

It depends on your goal. Easy aerobic and recovery work usually sits around 50% to 70% of heart rate reserve, steady tempo and threshold efforts around 70% to 90%, and short high-intensity intervals near 90% to 100%. Set the low and high ends to match the session you are planning, then read the matching beats-per-minute range.

No. This tool is for education and general fitness planning, not a substitute for professional medical advice. Estimated maximum heart rates carry a wide individual margin of error, so treat the numbers as a starting point. If you have a heart condition, take medication that affects heart rate, or are new to exercise, talk to a doctor before training to a target heart rate.