How to use the heart rate zone calculator
· Reviewed against American Heart Association guidance
- 1
Enter your age. Type your age into the calculator. It is used to estimate your maximum heart rate.
- 2
Add your resting heart rate (optional). Open settings and enter your resting heart rate to switch to the more personalized Karvonen heart rate reserve method.
- 3
Choose a formula (optional). Pick the Fox, Tanaka, or Gulati formula for estimating maximum heart rate. Gulati is validated for women.
- 4
Read your five zones. Your five training zones are shown instantly in beats per minute, along with your estimated maximum heart rate.
The 5 heart rate training zones explained
Each zone is a percentage range of your maximum heart rate, and each trains a different part of your fitness. Most people spend the majority of their time in Zones 1–2 and use short, targeted efforts in Zones 4–5.
Zone 1 — Very easy
50–60% of max HR- Feels like:
- A gentle effort you could keep up all day. Breathing stays relaxed.
- Good for:
- Warm-ups, cool-downs, and recovery between harder sessions.
Zone 2 — Easy (aerobic base)
60–70% of max HR- Feels like:
- Conversational — you can talk in full sentences. The classic fat-burning pace.
- Good for:
- Building aerobic endurance and the bulk of weekly training volume.
Zone 3 — Moderate (tempo)
70–80% of max HR- Feels like:
- Working, but controlled. Talking gets harder.
- Good for:
- Improving aerobic capacity and steady-state stamina.
Zone 4 — Hard (threshold)
80–90% of max HR- Feels like:
- Comfortably hard. You can only manage a few words at a time.
- Good for:
- Raising your lactate threshold and race-pace fitness.
Zone 5 — Maximum (VO₂ max)
90–100% of max HR- Feels like:
- All-out. Sustainable only for short bursts.
- Good for:
- Developing top-end speed and VO₂ max with short intervals.
How heart rate zones are calculated
Zones are built from your maximum heart rate (MHR). This calculator estimates MHR from your age using one of three research-backed formulas:
- Fox: 220 − age — the classic, most widely used estimate.
- Tanaka: 208 − (0.7 × age) — more accurate across a wide age range.
- Gulati: 206 − (0.88 × age) — validated specifically for women.
Each zone is then a percentage of that number. If you add your resting heart rate, the calculator uses the Karvonen (heart rate reserve) method instead:
Target HR = ((MHR − RHR) × %) + RHR
Methods reflect the American Heart Association's exercise intensity guidelines and published research on maximum heart rate estimation (Tanaka et al., 2001; Gulati et al., 2010). Formulas are population averages and can differ from your true values by 10–20 bpm, so use the results as guidance rather than exact targets.
Frequently asked questions
How do you calculate heart rate zones?
Heart rate zones are bands of exercise intensity defined as a percentage of your maximum heart rate (MHR). This calculator first estimates your max heart rate from your age, then divides the range into five zones from 50% up to 100% of maximum. If you also enter your resting heart rate, it switches to the Karvonen (heart rate reserve) method, which personalizes the zones to your own fitness level.
What are the five heart rate training zones?
Zone 1 (50–60% of max) is very easy recovery effort. Zone 2 (60–70%) is an easy, conversational aerobic pace often called the fat-burning zone. Zone 3 (70–80%) is a moderate tempo effort. Zone 4 (80–90%) is hard, threshold-pace work. Zone 5 (90–100%) is maximum effort used for short, intense intervals. Each zone develops a different part of your fitness.
What is the most accurate way to calculate heart rate zones?
The Karvonen, or heart rate reserve, method is the most personalized because it accounts for your resting heart rate rather than your age alone. Add your resting heart rate in the calculator settings to use it. Age-only formulas are convenient but can be off by 10–20 bpm for any individual, so treat the results as a well-informed starting point.
How do I find my maximum heart rate?
The fastest way is an age-based formula. This calculator offers three: Fox (220 − age), Tanaka (208 − 0.7 × age), and Gulati (206 − 0.88 × age, validated specifically for women). For a precise number, a supervised maximum heart rate field test or a lab test is more accurate, because formulas are population averages and individuals vary.
What is Zone 2, the fat-burning heart rate zone?
Zone 2 is roughly 60–70% of your maximum heart rate — an easy pace at which you can still hold a conversation. Your body uses a higher proportion of fat for fuel at this intensity, and the majority of endurance training is done here because it builds your aerobic base with low fatigue.
Should I use maximum heart rate or heart rate reserve?
Percentage of maximum heart rate is the simplest method and needs only your age. The heart rate reserve (Karvonen) method is more individualized because it also factors in your resting heart rate, which reflects your current fitness. If you know your resting heart rate, the Karvonen method gives more tailored zones.
Is this heart rate zone calculator free?
Yes. The calculator is completely free, runs in your browser, and requires no sign-up. Enter your age — and optionally your resting heart rate — to see your five personalized heart rate training zones instantly.
About this calculator
This tool is built and maintained by the team behind Heart Rate Zone Calculator. The zone percentages follow the American Heart Association's exercise-intensity guidance, and the maximum-heart-rate formulas come from peer-reviewed research. The methodology and copy on this page were last reviewed in June 2026.
Sources
- American Heart Association — Target Heart Rates — Exercise intensity guidance (50–85% of maximum heart rate).
- Tanaka, Monahan & Seals (2001) — “Age-predicted maximal heart rate revisited,” J. Am. Coll. Cardiol.
- Gulati et al. (2010) — Heart rate response in women, Circulation — basis of the Gulati formula.