Free Heart Rate Zones Online

Heart Rate Zones Calculator: Turning Age and Resting Pulse Into Training Targets

A heart rate zones calculator takes two or three numbers you already know — your age, and optionally your resting pulse — and turns them into a set of five bpm ranges you can watch on a chest strap or wrist sensor while you train. Instead of guessing whether "moderate effort" means 120 beats per minute or 150, the zones give you a concrete number range to aim for, whether the goal is an easy recovery jog, a longer aerobic base ride, or a short, hard interval. This tool runs the calculation the moment you change an input, so there's no submit button to click and no waiting on a page reload — pick a method, type your age, and the zone list below updates instantly.

Everything here is informational and educational, built from population-level formulas rather than a lab test or a physician's assessment of your individual cardiovascular health. Treat the numbers as a reasonable starting point for structuring a workout, not a diagnosis or a prescription — this is an estimate, not medical advice. Anyone with a diagnosed heart condition, a history of chest pain or fainting during exercise, or other cardiovascular risk factors should talk to a cardiologist or physician before starting or meaningfully changing an exercise routine built around these zones, and if something feels wrong mid-workout (chest pain, dizziness, unusual shortness of breath), stop and seek medical attention rather than pushing through it because a number on a screen says you're still "in zone."

How to Use the Heart Rate Zones Calculator

1. Pick a calculation method from the three tabs at the top of the settings panel: Karvonen, which factors in your resting heart rate for a more individualized estimate; Zoladz, which subtracts a fixed number of beats from your estimated max for each zone boundary; or Max HR, the simplest option, which expresses each zone as a straight percentage of your estimated maximum heart rate.
2. Enter your age in the "Your Age" field. This feeds directly into the underlying maximum-heart-rate estimate that every method builds on.
3. If you selected Karvonen, enter your resting heart rate — ideally measured first thing in the morning before getting out of bed, when your pulse is at its lowest and most stable. This field is disabled for the other two methods, since they don't use it.
4. Read the "Max Heart Rate" card, which shows your estimated maximum pulse using the 220-minus-age formula, and, if you're using Karvonen, the "Heart Rate Reserve" card just next to it, which is simply the gap between your max and your resting rate.
5. Scroll down to the zone list, where five cards — Zone 1 through Zone 5 — each show a bpm range and a short description of what that intensity is generally used for, from warm-up and recovery work at the low end to short maximal efforts at the top.
6. Change the age, resting rate, or method at any point and every card recalculates immediately, so you can compare how the three methods disagree for the same age before settling on one to train with.

Why Runners, Cyclists, and Gym-Goers Look Up Heart Rate Zones

• Structuring an endurance training plan. Coaches commonly prescribe workouts by zone rather than by pace or watts alone, because heart rate reflects effort even when terrain, wind, or fatigue change what a given pace feels like — "45 minutes in zone 2" is a more portable instruction than "45 minutes at a 9:00 mile pace."
• Avoiding chronic overtraining. A large share of aerobic training is meant to happen at an easy, conversational effort (commonly zone 2), and it's easy to drift into zone 3 without noticing on an unstructured run — having a bpm ceiling makes that drift visible in real time on a watch or chest-strap display.
• Setting up a wearable or fitness watch. Most sports watches and fitness trackers let you program custom heart-rate zones for alerts and post-workout analysis, and this calculator is a quick way to get starting numbers to type into that device's settings before your first structured session.
• Understanding a cardiac stress test or gym orientation handout. Gyms, physical therapists, and cardiac rehab programs frequently reference "your zone 2" or "70% of max" in printed guidance, and it helps to know roughly what bpm range that phrase maps to for your age before your next session.
• Comparing training intensity across different sports. Because the zones are expressed as bpm rather than pace or power, the same five-zone framework carries over from running to cycling to rowing, which is useful for anyone cross-training across more than one sport.

The Formulas Behind the Zones

Every method on this page starts from the same building block: an estimated maximum heart rate. The most widely cited formula, and the one this calculator uses by default, is simply 220 minus your age — for a 30-year-old, that works out to 190 bpm. It's a population average derived from decades-old research, not a measurement of your actual physiology, and it carries a documented error margin of roughly plus or minus 10 to 12 beats per minute from one person to the next at the same age. A newer alternative, the Tanaka formula (208 minus 0.7 times age), tends to estimate a slightly lower max heart rate for older adults — the same 30-year-old comes out to about 187 bpm under Tanaka instead of 190 under 220-minus-age. Both are estimates; neither replaces a supervised maximal exercise test if you need a precise number.

Once a max heart rate is set, the zones themselves are drawn as five bands, most commonly at 50-60%, 60-70%, 70-80%, 80-90%, and 90-100% of that maximum:

Zone	% of max HR	bpm range (age 30, max HR 190)	General use
Zone 1	50-60%	95-114	Warm-up, cool-down, active recovery
Zone 2	60-70%	114-133	Easy aerobic / fat-burning effort
Zone 3	70-80%	133-152	Moderate, sustained cardio effort
Zone 4	80-90%	152-171	Hard, threshold-style effort
Zone 5	90-100%	171-190	Maximal, short-duration effort

The Karvonen method changes the base of that percentage from your raw max heart rate to your heart rate reserve — the gap between your max and your resting heart rate — and then adds your resting rate back on top of each percentage. For the same 30-year-old with a resting heart rate of 60 bpm, the reserve is 190 minus 60, or 130 bpm, and zone 3 becomes 70% and 80% of that 130, plus the 60 resting baseline: 151 to 164 bpm, noticeably different from the max-HR-only version above. Karvonen is generally considered a closer fit to individual fitness because it accounts for how efficiently your heart already works at rest, but it depends on an accurate resting-pulse measurement to be worth much — a reading taken after climbing a flight of stairs will throw every zone off.

Where These Estimates Fall Short

None of these formulas were built from your personal physiology, and a handful of common factors push the real number away from the estimate. Beta-blockers and certain other cardiovascular medications cap heart rate well below the 220-minus-age prediction, sometimes by 20-30 beats, which makes zone training by formula actively misleading for anyone on that class of drug. Genetics alone account for a meaningful spread even among healthy people of identical age — the plus-or-minus-10-to-12 bpm error band mentioned above is an average, and some individuals fall well outside it in either direction. Altitude, heat, dehydration, caffeine, illness, and poor sleep all shift heart rate at a given effort level on any single day, so a zone 3 run one week can feel like zone 4 the next without any change in fitness. And because the three methods on this page use different math, switching between Karvonen, Zoladz, and Max HR for the same age and resting rate will hand you three different bpm ranges labeled "zone 3" — pick one method and stay with it for a training block rather than bouncing between them.

Getting a More Precise Number

If formula-based estimates aren't precise enough for your training needs, a handful of alternatives exist, each with a different cost-to-accuracy tradeoff:

• A supervised maximal exercise test. A cardiologist, sports-medicine clinic, or exercise physiology lab can run a graded treadmill or bike test to directly observe your true maximum heart rate under medical supervision — the gold-standard option, and the right choice for anyone with cardiovascular risk factors before starting an intense program.
• Field tests. Experienced athletes sometimes estimate max heart rate from a hard, all-out effort at the end of a long warm-up, though this carries its own risk and isn't a substitute for medical clearance if you have any underlying heart condition.
• A sports watch with heart-rate-variability tracking. Some modern devices refine your zones over weeks of training data rather than relying on a static age-based formula, adjusting recovery and threshold estimates as they collect more readings from your own workouts.
• This calculator's API. If you're building a training app, coaching dashboard, or fitness spreadsheet and want the same zone math available programmatically, the calculation is exposed as a metered API endpoint that accepts age, an optional resting heart rate, and a choice of formula, returning the max heart rate and all five zones as structured JSON output — parameter details and the per-call credit cost are listed at the API reference.

Which method should I use — Karvonen, Zoladz, or Max HR?

Karvonen is the most commonly recommended of the three because it accounts for your resting heart rate, which is a rough proxy for cardiovascular fitness — a lower resting pulse generally means more room between rest and max, and a more individualized reserve to work from. Max HR is the simplest and needs only your age, making it a reasonable quick estimate if you don't have a reliable resting-pulse reading handy. Zoladz uses fixed beat offsets from max heart rate rather than percentages and is popular in some European training traditions; try it if a coach or training plan specifically references Zoladz zones.

Is 220 minus age still considered accurate?

It remains the most widely used formula because it's simple and was validated across a large body of older research, but more recent studies suggest it systematically overestimates max heart rate in older adults and underestimates it in some younger people. The Tanaka formula (208 minus 0.7 times age) is a commonly cited alternative that tends to track slightly better across a wider age range, though both remain population averages rather than individual measurements.

Why did my resting heart rate change the zone numbers so much?

Under the Karvonen method, your resting heart rate directly sets the size of your heart rate reserve — the range the percentages are calculated from — so a lower resting pulse widens that reserve and shifts every zone's bpm range. A single inaccurate resting reading, taken while stressed, caffeinated, or shortly after standing up, can noticeably skew every zone below it, which is why a calm, first-thing-in-the-morning measurement gives the most useful result.

Can I use these zones if I'm just starting to exercise?

The zone structure itself works for beginners as well as experienced athletes, but anyone new to structured exercise, returning after a long break, or managing an existing health condition should get clearance from a physician before starting, and should expect to spend most early sessions in the lower zones rather than chasing the higher-intensity ranges right away.

Related Health Tools

Heart rate zones are one piece of a broader training picture. Pair this calculator with the calories burned calculator to see roughly how much energy a session in a given zone costs, or the BMR calculator and TDEE calculator to understand the resting and total energy numbers your training sits on top of. If your training centers on strength work rather than cardio, the one-rep max calculator covers the equivalent intensity-targeting problem for lifting.