Heart rate zone calculator: find your training zones

The heart rate zone calculator turns your age and resting heart rate into five practical training zones, so you know what intensity to aim for whether you're doing an easy recovery session or a hard interval workout. It uses a more current formula for max heart rate than the well-known "220 minus age" rule, and calculates zones with the Karvonen method rather than simple percentages of max alone.

How to use the calculator

Enter your age and your resting heart rate (measured first thing in the morning before getting up, ideally averaged over a few days for accuracy — a fitness tracker or a manual pulse count both work). The calculator returns your estimated max heart rate and a table of five zones with a bpm range for each, from easy recovery pace up to near-maximal effort.

The Tanaka formula for max heart rate

This calculator estimates max heart rate using 208 − (0.7 × age), a formula developed by Tanaka, Monahan and Seals that is generally considered more accurate across a wider age range than the older "220 minus age" rule, which tends to overestimate max heart rate in older adults. Like any formula-based estimate, it's a population average — your true max heart rate can vary by 10–15 bpm or more from the formula's prediction, so treat it as a solid starting estimate rather than a lab-tested number, and adjust your perceived effort alongside the numeric target if a given zone consistently feels much easier or harder than it should.

The Karvonen method for training zones

Rather than simply taking a percentage of your max heart rate, the Karvonen method factors in your resting heart rate too, using your heart rate reserve (max minus resting) to calculate each zone: target = resting + (reserve × zone percentage). This gives more personalized zones than percentage-of-max alone, since two people with the same max heart rate but very different fitness levels (and therefore different resting heart rates) will get meaningfully different target zones.

What each zone is for

Zone 1 (50–60% of reserve) is very easy recovery pace. Zone 2 (60–70%) is the classic "fat-burning" and aerobic-base zone — a pace you could hold a conversation at, and the zone most endurance coaches recommend spending the majority of training time in. Zone 3 (70–80%) is a moderate aerobic effort, harder to sustain conversation in. Zone 4 (80–90%) is a hard, threshold-style effort used in interval training. Zone 5 (90–100%) is near-maximal effort, sustainable only for short bursts.

Does "fat-burning zone" actually burn more fat?

Zone 2 burns a higher percentage of calories from fat compared with very hard efforts, but harder efforts burn more total calories per minute, including more total fat calories, despite using a lower percentage from fat. In practice, overall calorie balance across your week matters far more for fat loss than which specific heart rate zone you trained in — Zone 2 is valuable for building aerobic fitness and is comfortable enough to sustain for longer, not because it's a magic switch for fat loss.

Using your zones in training

Pair zone targets with the interval timer for structured intervals in Zone 4–5, or use Zone 2 as your target for longer, easier cardio sessions on the treadmill, bike or rowing machine. The calories burned calculator estimates the energy cost of a session at any of these intensities, and the interval timer's work-rest presets map reasonably well onto Zone 4–5 efforts if you want a fixed structure to follow rather than watching a heart rate monitor throughout.

Safety and when to check with a doctor

If you have a heart condition, take medication that affects heart rate (such as beta blockers), or are new to structured exercise, check with a doctor before using heart rate zones to guide hard interval training, since these formulas assume a typical, healthy heart rate response. Stop any session for chest pain, dizziness, or unusual breathlessness regardless of what zone you're targeting, and build up training volume in higher zones gradually over several weeks rather than jumping straight into hard interval work.

Privacy

Your age and resting heart rate are used only to calculate zones instantly in your browser — nothing is stored or sent anywhere.