Heart rate zone calculator (with zone 2)

Your maximum heart rate is roughly 208 − 0.7 × your age (the Tanaka formula), so about 187 beats per minute at 30. Training zones are percentages of that number: zone 2, the easy endurance zone, is 60 to 70% of max, or about 112 to 131 bpm for a 30-year-old. If you know your resting pulse, the Karvonen method gives more personal zones.

How the zones are calculated

Step 1: estimate max heart rate. The calculator offers two formulas.

• Tanaka: 208 − 0.7 × age. In 2001, Tanaka, Monahan and Seals pooled 351 studies covering 18,712 people (Journal of the American College of Cardiology) and confirmed the equation in a lab study of 514 healthy adults. It didn't differ by sex or fitness level.
• 220 − age. The old classic. It's simple, but the same paper found it underestimates max heart rate in older adults and overestimates it in younger ones.

The two agree around age 40 and drift apart after that. At 60, Tanaka gives 166 and 220 − age gives 160.

If you've done a genuinely all-out effort, such as the last minute of a hard 5 km race, and seen a higher number on a chest strap, enter that as your measured max. It beats any formula.

Step 2: turn percentages into beats per minute.

• Without a resting pulse, each zone is a percentage of max: zone 2 = 0.6 × max to 0.7 × max.
• With a resting pulse (Karvonen), the percentage is applied to your heart rate reserve, the gap between max and resting: target = resting + % × (max − resting). Fitter people with low resting pulses get zones that better match how hard the effort feels.

Worked example

You're 30 with a resting pulse of 60.

• Max (Tanaka) = 208 − 0.7 × 30 = 187 bpm
• Zone 2 by % of max = 0.6 × 187 to 0.7 × 187 = 112 to 131 bpm
• Heart rate reserve = 187 − 60 = 127
• Zone 2 by Karvonen = 60 + 0.6 × 127 to 60 + 0.7 × 127 = 136 to 149 bpm

Karvonen zones run higher for the same percentage. Both are reasonable; pick one and stick with it so your training log stays comparable.

The five zones

Five-zone systems like this are a coaching convention, so different watches and apps draw the lines slightly differently. The American College of Sports Medicine position stand (Garber et al., 2011) uses broader bands: moderate intensity is 64 to 76% of max heart rate (or 40 to 59% of reserve), and vigorous is 77 to 95% of max (60 to 89% of reserve). Zones 2 and 3 above roughly cover ACSM's moderate band, and zones 4 and 5 cover vigorous.

Why zone 2 gets so much attention

Zone 2 is easy enough to do for 45 minutes to an hour, often, without wrecking your legs for leg day. It builds the aerobic base that makes every harder session feel easier, and a larger share of the energy comes from fat at this intensity. The catch is that "fat burning zone" is often misread. You burn more total calories, and more total fat over a week, by doing more exercise, not by staying in one zone. Zone 2 just lets you do more of it. The zone 2 cardio guide explains how to fit it around weights.

A practical check: in zone 2 you can talk in full sentences but wouldn't want to sing. If you're gasping, slow down, even if that means walking uphill instead of jogging.

How to use this in a gym

Most Indian gyms have treadmills, cross-trainers and bikes with heart rate grips, but grips are unreliable once you're moving. A chest strap or a recent fitness watch is far more accurate. A simple week for a beginner:

1. Two or three sessions of 30 to 45 minutes in zone 2 (incline walk, cycle or cross-trainer).
2. One short session of intervals in zone 4, after a few weeks of base.
3. Your weights sessions as usual. The beginner gym workout plan shows how to combine them.

Pair the cardio with a sensible calorie target from the calorie calculator if fat loss is the goal. Heart rate zones tell you how hard you're working; the calorie balance decides what happens to your weight. To track strength alongside cardio, the one-rep max calculator gives you training loads.

Limitations

Age-based formulas describe averages. Individuals of the same age can differ by 10 to 20 bpm, so your real zones may be shifted. Heat, dehydration, caffeine, poor sleep and stress all push heart rate up for the same effort, which matters in an Indian summer. Medicines such as beta blockers lower heart rate and make these zones meaningless; if you have a heart condition, high blood pressure, or get chest pain, dizziness or unusual breathlessness during exercise, stop and see a doctor before training by heart rate.

This calculator is for general information and isn't medical advice.