Heart Rate Zone and VO2 Max Calculator

How hard is your workout?

Your heart rate is a simple guide to effort. Walking briskly, cycling or swimming at a moderate pace raises it into one band; running, fast cycling or hard sport push it higher. Knowing your own numbers helps you train at the effort you intend rather than guessing.

This heart rate zone calculator estimates your maximum heart rate from your age, then gives the target ranges for moderate and vigorous activity. Add your resting pulse and it also estimates VO2 max, a measure of aerobic fitness.

How to use it

1. Enter your age. The calculator estimates your maximum heart rate as 220 minus your age.
2. If you have measured your real maximum in a supervised test, enter it to use instead.
3. For VO2 max, count your resting pulse for a full minute just after waking, and enter it.
4. Read your moderate and vigorous ranges in beats per minute, and check them during exercise with a watch or by feeling your pulse.

The formulas

maximum heart rate ≈ 220 − age
moderate activity: 64 to 76% of maximum
vigorous activity: 77 to 93% of maximum
VO2 max ≈ 15.3 × maximum ÷ resting heart rate

The maximum heart rate estimate and the two target ranges follow the CDC’s guidance on measuring physical activity intensity. The VO2 max estimate is the heart rate ratio method of Uth and colleagues (2004), developed in trained men; it is a rough guide for everyone else.

Worked example: age 40, resting pulse 60

• Maximum: 220 − 40 = 180 bpm
• Moderate: 180 × 0.64 to 0.76 = 115 bpm to 137 bpm
• Vigorous: 180 × 0.77 to 0.93 = 139 bpm to 167 bpm
• VO2 max: 15.3 × 180 ÷ 60 = 45.9 mL/kg/min

At 40, a heart rate of 115 bpm to 137 bpm means moderate effort, and 139 bpm to 167 bpm means vigorous effort. The estimated VO2 max is 45.9 mL/kg/min, meaning the body can use about 45.9 mL of oxygen per kilogram each minute at full effort.

Target ranges by age

Age based estimates can be off by a fair margin for an individual, and some medicines, such as beta blockers, lower heart rate. The talk test is a useful check: at moderate effort you can talk but not sing; at vigorous effort you can say only a few words.

Using your zones

• Most adults are advised to do a mix of moderate and vigorous activity across the week.
• Spend most easy sessions in the moderate range; save the vigorous range for shorter, harder efforts.
• A falling resting heart rate over months is often a sign of improving fitness.
• For pace on runs, see the running pace calculator; for daily energy use, the calorie calculator.

Frequently asked questions

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