Target Heart Rate Calculator

What is a target heart rate calculator?

A target heart rate calculator estimates your maximum heart rate from your age and then translates the five training zones into a beats-per-minute (bpm) range you can actually aim for during exercise. Instead of guessing how hard you are working, you get concrete numbers: how fast your heart should beat for an easy warm-up, a fat-burning jog, a steady aerobic run, a hard interval, or an all-out effort.

The tool above needs just one input — your age — to work. Add an optional resting heart rate and it switches to the more personalised Karvonen method. Either way, you instantly see your maximum heart rate and the bpm window for each zone, so you can train at the right intensity for your goal.

How does the target heart rate calculator work?

The calculator starts with the standard age-based estimate of maximum heart rate:

• max HR = 220 − age

It then defines five training zones as a percentage of that maximum:

• Zone 1 — 50-60% (very light, warm-up/recovery)
• Zone 2 — 60-70% (fat burn)
• Zone 3 — 70-80% (aerobic, endurance)
• Zone 4 — 80-90% (anaerobic, threshold)
• Zone 5 — 90-100% (maximum effort)

If you leave resting heart rate blank, each zone is simply that percentage of your max HR. If you enter a resting heart rate, the tool uses the Karvonen formula, which is based on your heart rate reserve (the gap between max and resting):

• target = (max HR − resting HR) × intensity% + resting HR

The terms are simple:

• age — your age in whole years, used to estimate max HR.
• max HR — the highest your heart is expected to beat, in bpm.
• resting HR — your heart rate at complete rest, ideally measured first thing in the morning, in bpm.
• intensity% — the lower and upper bound of each zone (for Zone 2, 0.60 and 0.70).

All results are shown in bpm. Because Karvonen adds your resting rate back in, its targets are usually higher than the plain percent-of-max numbers.

Examples

These worked calculations match the tool’s output exactly.

Example 1 — Age 30, percent-of-max (no resting rate)

• max HR = 220 − 30 = 190 bpm
• Zone 2 (fat burn, 60-70%): 190 × 0.60 = 114 and 190 × 0.70 = 133 → 114-133 bpm

Example 2 — Age 30 with resting HR 60 (Karvonen)

• max HR = 190, heart rate reserve = 190 − 60 = 130
• Zone 2 lower: 130 × 0.60 + 60 = 78 + 60 = 138
• Zone 2 upper: 130 × 0.70 + 60 = 91 + 60 = 151
• Zone 2 = 138-151 bpm (higher than Example 1 because resting HR is added back in)

Example 3 — Age 40, percent-of-max

• max HR = 220 − 40 = 180 bpm
• Zone 3 (aerobic, 70-80%): 180 × 0.70 = 126 and 180 × 0.80 = 144 → 126-144 bpm
• Zone 4 (anaerobic, 80-90%): 180 × 0.80 = 144 and 180 × 0.90 = 162 → 144-162 bpm

Example 4 — Age 50 with resting HR 70 (Karvonen)

• max HR = 220 − 50 = 170, reserve = 170 − 70 = 100
• Zone 3 lower: 100 × 0.70 + 70 = 70 + 70 = 140
• Zone 3 upper: 100 × 0.80 + 70 = 80 + 70 = 150
• Zone 3 = 140-150 bpm

Heart rate zone reference table

The table below shows each zone as a percent-of-max bpm range, calculated straight from max HR = 220 − age. Values are rounded to whole bpm.

Zone (intensity)	Age 25 (max 195)	Age 35 (max 185)	Age 45 (max 175)	Age 55 (max 165)
Zone 1 — 50-60%	98-117	93-111	88-105	83-99
Zone 2 — 60-70% (fat burn)	117-137	111-130	105-123	99-116
Zone 3 — 70-80% (aerobic)	137-156	130-148	123-140	116-132
Zone 4 — 80-90% (anaerobic)	156-176	148-167	140-158	132-149
Zone 5 — 90-100% (max)	176-195	167-185	158-175	149-165

Read down a column for your age, or enter your exact age (and resting rate) in the tool for precise numbers. Note that these are percent-of-max values; adding a resting heart rate via Karvonen shifts each range upward.

Common uses

A target heart rate range guides almost any cardio session:

• Fat-burning workouts. Stay in Zone 2 for longer, lower-intensity sessions where a high share of energy comes from fat.
• Building endurance. Use Zone 3 for steady aerobic runs, rides or swims that grow your aerobic base.
• Interval and threshold training. Push into Zone 4 for hard intervals and tempo work that raise your lactate threshold.
• Recovery and warm-ups. Keep easy days and warm-ups in Zone 1 so you do not overload your training.
• Pacing races. Match effort to a planned zone so you do not start too fast and fade.

Tips and common mistakes

• Add your resting heart rate. Karvonen personalises your zones; the plain percent-of-max method ignores your fitness level entirely.
• Measure resting HR correctly. Take it after waking, before getting up or drinking caffeine, for the truest number.
• 220 − age is an estimate. Real max HR varies by 10-20 bpm between people of the same age, so treat the figure as a starting point.
• Do not confuse the two methods. For age 30, Zone 2 is 114-133 bpm by percent-of-max but 138-151 bpm by Karvonen with a resting rate of 60 — same person, different reference.
• Use a chest strap for accuracy. Wrist optical sensors can lag or misread during hard or cold sessions.
• Round sensibly. A target of 133.0 bpm just means roughly 133; aim for the range, not a single beat.

Limitations and notes

The 220 − age formula is a population estimate, not a measurement of your own maximum heart rate. Studies show wide individual variation, and the formula tends to slightly over-estimate max HR for younger people and under-estimate it for older people. Medications such as beta-blockers, fitness level, altitude, heat, caffeine, stress and sleep all shift heart rate on any given day. The Karvonen method is more individual because it uses your resting rate, but it still depends on the same estimated maximum. For a true maximum or precise zones, a supervised exercise (stress) test is the gold standard.

Health disclaimer: This target heart rate calculator is provided for general information and education only. It is not medical or fitness advice and is not a substitute for professional assessment. If you have a heart condition, take heart-rate-affecting medication, or are new to exercise, consult a qualified healthcare professional before training to these numbers.

For more health self-checks, try the BMI calculator to gauge weight for height, the BMR calculator for resting calorie burn, or the body fat calculator to estimate body composition, and browse the full health & medical category for more tools.