MAF Heart Rate Calculator

Age

Your training and health status — select the option that best describes you

Your MAF Heart Rate

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bpm (upper limit)

Training zone: — – — bpm

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Base (180 − age)

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Adjustment applied

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MAF upper limit (bpm)

💡 What this means

What is the MAF 180 Formula?

The MAF (Maximum Aerobic Function) 180 Formula was developed by Dr. Phil Maffetone in the 1980s after years of working with endurance athletes. The core calculation is simple: 180 minus your age, adjusted based on your current health and training history. The result is your MAF heart rate — the upper ceiling for aerobic base training.

Unlike percentage-based zone calculations (like the standard Zone 2 approach), the MAF formula doesn't rely on estimated maximum heart rate. Instead, it uses age and individual health status to arrive at a personalised number that reflects your body's actual aerobic threshold more accurately for many people.

Training at or below your MAF heart rate ensures you're working primarily within the aerobic energy system — burning fat as your main fuel, building mitochondrial density, and developing cardiovascular efficiency without triggering the stress hormones and recovery burden associated with higher-intensity work.

The four adjustment categories

Maffetone built adjustment factors into the formula to account for individual variation. These are applied to the base number (180 − age):

−10 bpm: If you are recovering from a major illness, injury, surgery, or overtraining syndrome. Also applies if you are on regular medication for a chronic condition, or have frequent illness (more than two colds per year).
−5 bpm: If you have been inconsistent with training (more than two years without regular exercise), or if you are just starting out. Also applies if you have noticed regression in your fitness or performance recently.
No adjustment (0): If you have been training consistently for at least two years with no major health issues, injuries, or setbacks.
+5 bpm: If you have trained consistently for two or more years and have been making clear, measurable improvements in fitness and performance without illness or injury setbacks.

Your MAF training zone

Once you have your MAF heart rate (the upper limit), your aerobic training zone extends from 10 bpm below your MAF up to your MAF. For example, if your MAF is 140 bpm, your training zone is 130–140 bpm. Most of your aerobic base training should be done within this 10-bpm window, with the aim of staying at or below the ceiling rather than always pushing to it.

MAF vs Zone 2: what's the difference?

Both MAF training and Zone 2 training target the aerobic energy system, but they arrive at the target heart rate differently. Here's how they compare:

Feature	MAF (Maffetone)	Zone 2 (% of Max HR)
Calculation basis	Age + health/training status	Estimated max heart rate
Accounts for individual health	Yes — adjustment factors	No
Relies on max HR estimate	No	Yes (often inaccurate)
Result	Single upper-limit number	A range (60–70% max HR)
Tends to be	More conservative	Sometimes higher
Best for	Building aerobic base; injury prevention	General aerobic fitness guidance

For many people, especially those with injury history, inconsistent training, or health conditions, the MAF formula gives a more conservative and therefore safer training ceiling than a standard Zone 2 calculation. If you find MAF and Zone 2 give you very different numbers, it's worth reflecting on which adjustment category applies to you honestly.

Why training below your MAF matters

Many people — particularly those coming from high-intensity backgrounds — find MAF training frustratingly slow at first. That's by design. When you consistently exceed your aerobic threshold (your MAF heart rate), you begin recruiting the anaerobic energy system and burning glycogen rather than fat. Over time, this pattern limits aerobic development, increases recovery demands, and can lead to a plateau or regression in performance.

By staying strictly below MAF, even when it means slowing to a walk, you allow the aerobic system to develop fully. As aerobic capacity improves, your pace at the same heart rate will increase — meaning you'll be running faster at the same effort over the weeks and months ahead. This is often called the "MAF test": tracking your pace at your MAF heart rate over time is one of the clearest measures of aerobic progress.

How long does MAF training take to work?

Most athletes notice measurable aerobic improvement — running or cycling faster at the same MAF heart rate — within 4 to 8 weeks of consistent, disciplined low-HR training. Full aerobic base development, where the gains become significant and sustained, typically takes 3 to 6 months. Maffetone recommends a dedicated base-building phase of at least 3 months before reintroducing any high-intensity work.

Consistency matters far more than session length. Three to five sessions per week of 30–60 minutes each, all kept below MAF, will produce better long-term aerobic development than occasional longer efforts that drift above the ceiling.

Practical tips for MAF training

Use a heart rate monitor you trust: A chest strap is more accurate than a wrist optical sensor, especially during running. You need real-time feedback to stay disciplined about the ceiling.
Don't chase the number: The goal is to stay at or below MAF, not to constantly push up to it. Many of your sessions should be done comfortably below the ceiling.
Accept the pace: Especially in the first few weeks, MAF training will feel very easy — often disconcertingly so. Walking sections are completely normal and expected.
Track your MAF test: Once a month, do a timed 5 km or 30-minute effort at exactly your MAF heart rate. Record your pace. This is your clearest measure of aerobic progress.
Avoid intensity for the first phase: During a dedicated base-building phase (ideally 3 months), eliminate hard intervals and tempo work. All cardio should be aerobic.
Reassess your category every 3–6 months: As fitness improves, you may move into a higher adjustment category. Recalculate accordingly.

Frequently asked questions

How is MAF different from Zone 2?

Both target the aerobic energy system, but the calculation method differs. Zone 2 is typically defined as 60–70% of your estimated maximum heart rate (220 − age). MAF uses 180 − age adjusted for health and training history. MAF doesn't rely on max HR estimation and accounts for individual circumstances. For many people, especially those with injury history or inconsistent training, MAF gives a more conservative (and safer) ceiling than a standard Zone 2 calculation.

What if MAF gives me a very low number?

This is common, especially for older adults or those who apply a negative adjustment. A MAF of 120 bpm or even lower is entirely valid — it may mean brisk walking is your aerobic training pace right now. That's not a problem; it's simply where your aerobic base needs to be built from. As fitness improves, your pace at that heart rate will increase even if the number itself doesn't change much.

Can I do strength training while doing MAF aerobic base building?

Yes — strength training doesn't conflict with MAF base building. The MAF protocol applies to aerobic cardio sessions only. Lifting, bodyweight work, and resistance training can continue normally during a base-building phase. Just keep your aerobic cardio sessions strictly below your MAF ceiling.

Is the MAF formula accurate for older athletes?

The MAF formula was designed for ages roughly 16–65. For athletes over 65, the resulting number can become quite low (e.g., 180 − 70 = 110 bpm), which may feel extremely conservative. Maffetone acknowledged this and suggested older athletes who are genuinely fit and healthy could apply the +5 adjustment if they meet the criteria. Individual response varies, and working with a coach familiar with MAF training can help calibrate the formula for older athletes.

How do I know which adjustment category to choose?

Be honest with yourself. If you've had any illness, injury, or health setback in the past year, apply at least the −5 adjustment. If you're returning after a significant break, use −5 or −10. If you've been training consistently for 2+ years with no problems, use 0. The +5 is reserved for athletes who have genuinely been progressing — not just training, but getting measurably fitter. When in doubt, the more conservative option is safer and still produces excellent results.

How often should I recalculate my MAF heart rate?

Your MAF heart rate changes with age (it decreases by 1 bpm per year) and can change if your health or training status category shifts. A practical approach is to recalculate every 6–12 months, or immediately if there's a significant change in your health or training consistency. Even if the number stays the same, the pace you can achieve at that heart rate should increase as fitness improves.

Not medical advice. The MAF 180 Formula is an estimation tool based on population data. Individual aerobic thresholds vary. If you have cardiovascular disease, a heart condition, or other serious health concerns, consult a doctor before beginning any exercise programme. Heart rate zones are starting points — adjust based on how your body responds over time.