Heart Rate Zone Calculator
Find your 5 training zones by age
Calculation Method
Maximum Heart Rate
190 bpm
220 − 30 = 190 bpm
Zone Spectrum
95–114
bpm
Very easy
Can sing
114–133
bpm
Easy / fat burn
Full conversation
133–152
bpm
Moderate / cardio
Short sentences
152–171
bpm
Hard / threshold
A few words
171–190
bpm
Max / VO₂ max
Cannot speak
| Zone | BPM Range | % of MHR |
|---|---|---|
| Zone 1 — Active Recovery | 95–114 bpm | 50–60% |
| Zone 2 — Aerobic Base | 114–133 bpm | 60–70% |
| Zone 3 — Aerobic Threshold | 133–152 bpm | 70–80% |
| Zone 4 — Anaerobic Threshold | 152–171 bpm | 80–90% |
| Zone 5 — Maximum Effort | 171–190 bpm | 90–100% |
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What is the Heart Rate Zone Calculator?
The Heart Rate Zone Calculator finds your five personalized heart rate training zones based on your age and, optionally, your resting heart rate. Each zone corresponds to a different exercise intensity, a different primary energy system, and different physiological adaptations — from light recovery work at Zone 1 to all-out sprinting at Zone 5.
The calculator supports two methods. The age-based method uses the universal 220-minus-age formula to estimate your maximum heart rate, then derives zones as percentages of that maximum. The Karvonen method incorporates your resting heart rate to calculate your heart rate reserve — a more physiologically accurate approach that accounts for your individual cardiovascular fitness level.
Knowing your zones lets you train with precision rather than effort, and makes the difference between building an aerobic base efficiently (by staying in Zone 2) and accidentally doing most of your training at a moderate intensity that develops neither aerobic base nor speed.
The five heart rate training zones explained
Zone 1 — Active Recovery (50–60% MHR)
Zone 1 is genuinely easy exercise — a slow walk, a very gentle jog, or easy cycling where you can hold a comfortable conversation without any breathlessness. Your body is running almost entirely on aerobic metabolism, using fat and a small amount of carbohydrate as fuel, and the cardiovascular system is under minimal stress.
The primary use of Zone 1 is active recovery: the light movement increases blood flow to muscles without adding training stress, clearing metabolic waste products and reducing soreness after hard workouts. It also has a place in long easy endurance sessions where staying below the aerobic threshold protects recovery capacity for harder training days. For beginners, Zone 1 and the lower end of Zone 2 form the foundation of any fitness programme.
Zone 2 — Aerobic Base (60–70% MHR)
Zone 2 is often called the fat-burning zone, the aerobic base zone, or the conversational zone. At this intensity your body is primarily burning fat for fuel — not because fat is the "cleanest" fuel source, but because this intensity sits below the lactate threshold where carbohydrate combustion ramps up dramatically. Mitochondrial density (the density of the cellular power plants that process aerobic metabolism) increases most effectively in Zone 2.
Elite endurance athletes spend 70–80% of their total training volume in Zone 2. The research behind this polarized training model shows that high volumes of Zone 2 work, combined with small amounts of Zone 4–5 intensity, produces better long-term aerobic development than spending most training time in the moderate Zone 3 range. For recreational athletes, Zone 2 is the zone that produces sustainable cardiovascular fitness over months and years without accumulating fatigue.
Zone 3 — Aerobic Threshold (70–80% MHR)
Zone 3 is a moderate effort — you can still talk, but only in short sentences rather than full paragraphs. The body is now burning a roughly equal mix of fat and carbohydrate. You're working hard enough that fatigue begins to accumulate over sessions, but the intensity isn't high enough to drive the specific adaptations of Zone 4 threshold training.
Zone 3 has a somewhat controversial place in endurance science. The polarized training model — endorsed by research on elite athletes — suggests that too much Zone 3 work leads to a "moderate intensity trap" where athletes accumulate fatigue without the cardiovascular benefits of easy Zone 2 work or the power and speed gains of Zone 4–5 work. That said, Zone 3 is still a legitimate training zone for general fitness, tempo sessions, and sport-specific training where sustained moderate efforts are required.
Zone 4 — Anaerobic Threshold (80–90% MHR)
Zone 4 is hard, sustained effort — tempo running, threshold intervals, or a sustained effort you could maintain for 20–60 minutes but not much longer. At this intensity, lactate production begins to exceed the body's ability to clear it, and the primary fuel source has shifted almost entirely to carbohydrate. You can speak a few words but not hold a conversation.
Zone 4 is the zone that most directly improves your lactate threshold — the pace at which you can sustain an effort before lactate accumulation forces you to slow down. Raising this threshold is the single most effective way to improve performance in endurance events. Common Zone 4 workouts include 20-minute threshold intervals, cruise intervals (4–6 × 8–10 minutes), and tempo runs at a comfortably hard sustained pace.
Zone 5 — Maximum Effort (90–100% MHR)
Zone 5 represents near-maximal to maximal effort — sprints, VO₂ max intervals, and all-out efforts that can only be sustained for seconds to a few minutes. The body is running almost entirely on carbohydrate, lactate accumulates rapidly, and you cannot speak more than a single word. Recovery between Zone 5 efforts takes significant time.
Zone 5 training increases VO₂ max — the maximum rate at which your body can consume oxygen — and improves neuromuscular power and top-end speed. Typical Zone 5 workouts include 30-second to 3-minute intervals at near-maximal effort with long rest periods (2:1 or 3:1 rest-to-work ratio). Because Zone 5 training is highly stressful, most training plans limit it to one or two sessions per week, with the majority of volume at Zone 2.
How to calculate maximum heart rate
The maximum heart rate (MHR) is the highest heart rate your cardiovascular system can achieve. It is genetically determined, decreases predictably with age, and is independent of fitness level — a highly trained marathon runner and a sedentary person of the same age have roughly the same maximum heart rate.
The 220-minus-age formula is the most widely used estimate and forms the basis of this calculator's age-based method. It was derived from pooled data across large populations and gives a reliable population average. However, individual variation is substantial: the standard deviation around the 220-age prediction is ±10–12 bpm, meaning roughly two-thirds of people have a true MHR within 10–12 bpm of the formula's estimate, and one-third are outside that range.
An alternative formula, developed by Tanaka et al. (2001) and based on a larger dataset, gives: MHR = 208 − (0.7 × age). This formula is considered slightly more accurate, particularly for older adults where the 220-age formula tends to overestimate MHR. The difference is small for most ages (a 40-year-old gets 180 from 220-age vs. 180 from Tanaka as well — they converge) but diverges at the extremes.
If you want to find your true MHR rather than estimating it, the only reliable method is a maximal effort test under supervision — typically a graded treadmill or cycling test where intensity increases incrementally until you reach exhaustion. This is not recommended without medical clearance, particularly for people over 40 or with cardiovascular risk factors.
The Karvonen method: why resting heart rate matters
The simple age-based method calculates zones as flat percentages of your maximum heart rate — Zone 2 is always 60–70% of MHR regardless of your fitness level. The Karvonen method refines this by incorporating your resting heart rate, which varies significantly between individuals and reflects cardiovascular fitness directly.
Your heart rate reserve (HRR) is the difference between maximum and resting heart rate: HRR = MHR − RHR. A very fit athlete with MHR 190 and RHR 45 has an HRR of 145. A sedentary person with the same MHR but RHR of 75 has an HRR of only 115. The Karvonen formula calculates zone boundaries as: target HR = RHR + (HRR × zone percentage).
The practical result: the Karvonen method shifts zone boundaries higher in absolute BPM terms for more fit individuals (who have lower resting rates), and keeps them lower for less fit individuals. This more accurately reflects the physiological reality — a trained athlete's Zone 2 genuinely corresponds to higher absolute heart rates than an untrained person's Zone 2, because their heart is more efficient and pumps more blood per beat.
For casual exercisers and beginners, the difference between methods is small enough to be irrelevant. For trained athletes who want precise zone boundaries for structured training, the Karvonen method is the better choice — and requires only that you know your resting heart rate, which you can measure at home in two minutes.
Zone 2 training: the aerobic base
Zone 2 has received significant attention in recent years following research into the training methods of elite endurance athletes and popularized by endurance medicine practitioners. The key insight is that most recreational athletes train too hard — spending the majority of their training time in Zone 3 (moderate intensity) rather than in the Zone 2 range where the most valuable aerobic adaptations occur.
The primary adaptation from Zone 2 training is mitochondrial biogenesis — the creation of new mitochondria within muscle cells. More mitochondria means greater aerobic capacity and improved fat oxidation efficiency. These adaptations develop slowly but permanently over months of consistent Zone 2 work. Zone 4 and 5 training produces speed and threshold improvements but does not drive the same mitochondrial development that Zone 2 delivers.
A practical gauge for Zone 2 without a heart rate monitor is the "nose test" or "conversational pace": you should be able to breathe comfortably through your nose throughout the effort and hold a complete conversation without gasping. If you can't maintain nasal breathing, you're above Zone 2. Many athletes who wear heart rate monitors discover that their typical "easy run" pace pushes them solidly into Zone 3 — and slowing down to genuinely stay in Zone 2 feels uncomfortably slow at first.
How to measure your resting heart rate accurately
Your resting heart rate (RHR) is the number of times your heart beats per minute when you are completely at rest. It is most accurately measured first thing in the morning, before getting out of bed, after waking naturally (not via an alarm if possible).
To measure manually: place two fingers (index and middle) on your wrist (radial artery) or neck (carotid artery). Count beats for 60 full seconds. Alternatively, count for 30 seconds and multiply by 2. For accuracy, take readings on three consecutive mornings and average the results — a single measurement can be affected by sleep quality, hydration, and stress.
- Normal adult RHR: 60–100 bpm (average around 70–75 bpm)
- Trained athlete RHR: 40–60 bpm (some elite endurance athletes reach 28–35 bpm)
- Elevated RHR (90+ bpm): May indicate stress, illness, dehydration, or overtraining — rest and re-measure the following day
Wearable fitness trackers (Garmin, Polar, Apple Watch, Fitbit) measure resting heart rate automatically overnight and provide a reliable average. If you have a device, use the 7-day average rather than a single measurement for the most accurate Karvonen zone calculation.
Heart rate zones for different training goals
Different fitness goals call for different zone emphases. Here's how to structure training volume across the zones for common goals:
| Goal | Z1–2 | Z3 | Z4–5 |
|---|---|---|---|
| Fat loss / general health | 70–80% | 10–20% | 5–10% |
| Aerobic base building | 80–90% | 5–10% | 5–10% |
| Endurance event prep | 75–80% | 5% | 15–20% |
| Speed / power improvement | 60–70% | 10% | 20–30% |
| Beginner fitness | 80–90% | 10% | 0–5% |
These are broad guidelines, not prescriptions. The optimal zone distribution for any individual depends on fitness level, recovery capacity, training history, and specific event demands. But for most recreational athletes, erring toward more Zone 2 and less moderate-intensity Zone 3 work produces better long-term outcomes.