Heart Rate Zone Calculator
Calculate your 5 heart rate training zones from your age or measured max heart rate. Includes Zone 2 training guide and the Tanaka max HR formula.
Heart rate zones tell you exactly how hard your body is working — and training in the right zone at the right time is the difference between building fitness and burning out. Enter your age or measured max heart rate to see your 5 training zones.
How to Calculate Max Heart Rate
Two commonly used formulas:
Classic formula (Haskell & Fox, 1970):
Max HR = 220 − age
Tanaka formula (more accurate, especially above age 40):
Max HR = 208 − (0.7 × age)
| Age | Classic (220 − age) | Tanaka (208 − 0.7×age) |
|---|---|---|
| 20 | 200 bpm | 194 bpm |
| 30 | 190 bpm | 187 bpm |
| 40 | 180 bpm | 180 bpm |
| 50 | 170 bpm | 173 bpm |
| 60 | 160 bpm | 166 bpm |
| 70 | 150 bpm | 159 bpm |
The Tanaka formula is generally preferred for older athletes. However, both are population averages with ±10–12 bpm standard deviation. The only way to know your true max HR is to measure it during a maximal effort test (e.g., at the end of a hard 5K race or a lab-based VO2 Max test).
The 5 Heart Rate Training Zones
| Zone | % of Max HR | BPM (for 180 bpm max HR) | Type | Primary benefit |
|---|---|---|---|---|
| Zone 1 | 50–60% | 90–108 bpm | Very easy | Active recovery, blood flow |
| Zone 2 | 60–70% | 108–126 bpm | Easy aerobic | Aerobic base, fat oxidation |
| Zone 3 | 70–80% | 126–144 bpm | Moderate | Aerobic fitness, tempo |
| Zone 4 | 80–90% | 144–162 bpm | Hard (threshold) | Lactate threshold, speed |
| Zone 5 | 90–100% | 162–180 bpm | Maximum | VO2 Max, short sprint intervals |
These percentages vary slightly between systems. Garmin, Polar, and Whoop use slightly different zone boundary percentages — the values above match the Karvonen method approximately.
Zone 2 Training — Why It's Having a Moment
Zone 2 (60–70% of max HR) has become one of the most discussed topics in endurance sports — popularised by researchers like Peter Attia, Inigo San Millan, and podcast discussions by Andrew Huberman.
Why Zone 2 matters:
- It primarily burns fat as fuel (low carbohydrate demand)
- It stimulates mitochondrial biogenesis — more mitochondria = better aerobic capacity
- It can be sustained for hours without meaningful recovery cost
- It's the zone where the aerobic base (the "engine") is built
How much Zone 2 is enough? Research from elite endurance athletes shows they spend approximately 75–80% of weekly training time in Zone 1–2 (the "80/20 rule"). For recreational runners, 3–4 hours per week of true Zone 2 running shows significant aerobic fitness improvements over 8–12 weeks.
The "talk test": Zone 2 should feel like you can speak full sentences comfortably. If you're breathing too hard to hold a conversation, you've drifted into Zone 3. Many recreational runners run their "easy" runs in Zone 3, which limits Zone 2 adaptation.
Personalised Zone Calculator
Using max HR = 175 bpm as an example:
| Zone | Min HR | Max HR | Typical use |
|---|---|---|---|
| Zone 1 | 88 bpm | 105 bpm | Warm-up, cool-down, rest day walk |
| Zone 2 | 105 bpm | 123 bpm | Easy runs, long run base pace |
| Zone 3 | 123 bpm | 140 bpm | Moderate runs, tempo start |
| Zone 4 | 140 bpm | 158 bpm | Threshold intervals, race effort |
| Zone 5 | 158 bpm | 175 bpm | Sprint intervals, hill sprints |
Resting Heart Rate and What It Tells You
Resting heart rate (measured first thing in the morning before getting up) is one of the simplest markers of cardiovascular fitness:
| Resting HR | Fitness category |
|---|---|
| Under 40 bpm | Elite athlete |
| 40–55 bpm | Excellent |
| 55–65 bpm | Good |
| 65–75 bpm | Average |
| 75–85 bpm | Below average |
| Over 85 bpm | Poor (see a doctor if persistent) |
Regular aerobic training typically lowers resting heart rate by 5–15 bpm over 6–12 months. A sudden increase of 5–10 bpm above your normal resting HR is often an early indicator of overtraining, illness, or inadequate recovery.
Heart Rate Variability (HRV)
HRV measures the variation in time between heartbeats. Unlike heart rate (beats per minute), HRV reflects the balance between the sympathetic (stress) and parasympathetic (recovery) nervous systems.
- High HRV: Well-recovered, low stress, ready for hard training
- Low HRV: Under-recovered, high stress, poor sleep — back off intensity
Devices like Whoop, Garmin (with HRV Status), Apple Watch, and Polar measure HRV. It's particularly useful for planning whether a scheduled hard workout should proceed or be replaced with Zone 1–2 work.
Frequently Asked Questions
What is the best heart rate zone for burning fat?
Zone 2 (60–70% of max HR) maximises the proportion of fat burned as fuel. However, total calorie burn is what matters for fat loss — Zone 4–5 training burns more total calories per minute, even though the fuel mix is more carbohydrate. For sustainable, injury-free training that also maximises fat oxidation efficiency, Zone 2 is ideal for most sessions.
Can I always use 220 minus my age?
The 220−age formula is a population average with a standard deviation of ±10–12 bpm. That means your actual max HR could easily be 175 or 195 if the formula predicts 185. For accuracy, measure your actual max HR during a hard 5K race (check HR in the final 400m) or do a lab test. The Tanaka formula (208 − 0.7×age) is slightly more accurate above age 40.
What happens if I train in Zone 3 too much?
"Zone 3 junk miles" — running too hard to get Zone 2 adaptation benefits, but not hard enough to get Zone 4 quality benefits — is the most common training mistake in recreational runners. It accumulates fatigue without building either the aerobic base (Zone 2) or speed (Zone 4). The 80/20 principle (80% Zone 1–2, 20% Zone 4–5) is more effective.
Why is my heart rate so high at the start of a run?
The initial spike in heart rate during the first 3–5 minutes is an overshoot response as your body quickly ramps up cardiac output to meet the demand of sudden exercise. This is normal. True Zone 2 assessment should be made 10–15 minutes into a run after heart rate has stabilised to a steady state.
What is the Karvonen method for heart rate zones?
The Karvonen method uses your Heart Rate Reserve (HRR = Max HR − Resting HR) instead of just Max HR. Zone boundaries are calculated as: Zone HR = Resting HR + (% × HRR). This method accounts for individual fitness level — a fit person with a low resting HR will have different zone boundaries than a sedentary person with the same max HR.
Related Calculators
- VO2 Max Calculator — estimate your aerobic fitness level
- Running Pace Calculator — find your Zone 2 training pace
- Calories Burned Calculator — estimate calorie burn by heart rate zone
- Marathon Pace Calculator — align marathon pace with heart rate zones