Heart Rate Zone Calculator

Training zones are percentages of your maximum heart rate expressed in beats per minute. Give the calculator your age and it estimates maximum with 220 − age, then slices it into five bands. Add your resting pulse and it switches to the Karvonen method, which puts every zone higher and ties them to your own fitness.

The five bands, and the two the AHA actually publishes

Zone	% of max HR	What it is for
Zone 1	50–60%	Warm-up, cool-down, active recovery
Zone 2	60–70%	Easy endurance you can hold for a long time
Zone 3	70–80%	Aerobic conditioning, steady runs and rides
Zone 4	80–90%	Threshold work, hard but repeatable intervals
Zone 5	90–100%	Short maximal efforts

It is worth knowing that this five-way split is a coaching convention, not a public health guideline. The American Heart Association describes intensity with two bands instead: moderate is about 50 to 70% of maximum, vigorous about 70 to 85%, and its published target zone runs 50 to 85% overall. Map that onto the table and zone 5 falls above anything the AHA charts as a target — which is a reasonable prompt to treat it as seasoning rather than a staple.

The same source sets the weekly dose: at least 150 minutes of moderate activity, or 75 minutes of vigorous, or a mix, with extra benefit up to 300 minutes.

Percent of max versus Karvonen, on one person

Take a 30-year-old with a resting pulse of 60. Maximum comes out at 190 bpm, so heart rate reserve is 130.

• Percent of maximum, zone 2 at 60–70%: 114 to 133 bpm.
• Karvonen, the same 60–70% of reserve added back onto resting: 138 to 151 bpm.

That is a 24-beat gap in the same band on the same person, which is why two people quoting “zone 2” can be describing genuinely different efforts. Neither is wrong; they answer different questions. Percent of maximum asks how close you are to your ceiling. Karvonen asks how far you have travelled from rest toward that ceiling. The Karvonen formula calculator walks through the arithmetic.

Getting the zones into your watch

Garmin, Polar, Coros and Apple all store zones as percentages, so the number you type in matters less than which basis you pick. Three things to check before you trust the screen:

• Basis. Look for a setting called ”% max HR” versus ”% HRR” or “heart rate reserve”. A watch set to reserve will disagree with a calculator set to maximum, exactly as above.
• Stored maximum. Many devices auto-update your maximum to the highest beat they ever saw, including a glitchy reading from a loose strap in cold weather. One bad spike can push every zone up for months.
• Wrist versus strap. Optical wrist sensors lag at the start of intervals and can lock onto cadence during running. For zone 4 and 5 work, a chest strap tells a straighter story.

Using the zones over a week, not a workout

A week that works usually looks lopsided: the bulk of the time in zones 1 and 2, one or two sessions touching zones 3 and 4, and zone 5 reserved for short, well-spaced efforts. Runners feel this most acutely, because easy running is what makes hard running survivable. If every run sits in zone 3, you are training the middle hard enough to be tiring and not hard enough to be a stimulus.

Without a monitor, the talk test tracks the same thing: in the moderate band you can still hold a conversation, in the vigorous band you can manage a few words at a time.

This content is informational and does not replace guidance from an exercise professional. Start from the max heart rate calculator if you have not estimated your ceiling yet, or compare against the target heart rate for exercise chart.