MAF Heart Rate Calculator

The 180 Formula was developed by Dr. Phil Maffetone, a sports physician and coach who worked with elite endurance athletes including six-time Ironman World Champion Mark Allen. The formula gives you a personalised upper heart rate limit for aerobic training, not a generic zone based on a percentage of your maximum heart rate but a number specific to your health and training history.

The base calculation is simple: 180 minus your age. From there, Dr. Phil Maffetone defined four adjustment categories. Subtract 10 if you have significant health issues, are recovering from illness, or are on regular medication. Subtract 5 if you've been training inconsistently, have minor health conditions, or are returning from injury. Make no adjustment if you've been training consistently for up to two years with good health. Add 5 if you've been training consistently for more than two years and are making steady competitive progress.

The resulting number is your MAF heart rate, the ceiling of your aerobic training zone. Dr. Phil Maffetone recommends training in the 10 bpm window below this number for all easy and base-building sessions. Over months of consistent training at or below this ceiling, your body adapts: it becomes more efficient at burning fat for fuel, your pace at the same heart rate improves, and the physiological stress that drives injury and overtraining is minimised.

The MAF method has been used by runners, cyclists, triathletes, and endurance athletes of all levels since the 1980s. A peer-reviewed paper co-authored by Dr. Phil Maffetone and published in Frontiers in Physiology (2020) provides clinical evidence for the approach.

Learn more about MAF training: if you're new to aerobic base training, our beginner's guide to MAF training walks you through the first steps. And if you're wondering how long it takes to see results, here's a month-by-month breakdown.