Training in zones makes sure easy days are easy and hard days are hard. Zone 2 builds your aerobic base; zones 4–5 build speed and threshold. Using resting heart rate makes the zones fit you better.
How to use the Heart Rate Zones Calculator
- Maximum heart rate formula
- Age (years)
- Maximum heart rate (bpm)
- Do you know your resting heart rate?
- Resting heart rate (bpm)
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Choose a formula (or enter your maximum heart rate), your age and, if you know it, your resting heart rate.
Inputs explained
| Field | What to enter |
|---|---|
| Maximum heart rate formula | Choose one: Fox: 220 − age, Tanaka: 208 − 0.7 × age, Nes: 211 − 0.64 × age, Inbar: 205.8 − 0.685 × age … |
| Age (years) | A number |
| Maximum heart rate (bpm) | A number |
| Do you know your resting heart rate? | Choose one: Yes: use Karvonen, No: % of maximum |
| Resting heart rate (bpm) | A number |
What each result means
- Heart rate reserve = [Maximum heart rate] – [B]
- Zone 1, Very light (50–60%) from = round([B] + 0.5×([Maximum heart rate] – [B]))
- up to = round([B] + 0.6×([Maximum heart rate] – [B]))
- Zone 2, Light / fat burning (60–70%) from = round([B] + 0.6×([Maximum heart rate] – [B]))
- up to = round([B] + 0.7×([Maximum heart rate] – [B]))
- Zone 3, Moderate / aerobic (70–80%) from = round([B] + 0.7×([Maximum heart rate] – [B]))
- up to = round([B] + 0.8×([Maximum heart rate] – [B]))
- Zone 4, Hard / anaerobic (80–90%) from = round([B] + 0.8×([Maximum heart rate] – [B]))
- up to = round([B] + 0.9×([Maximum heart rate] – [B]))
- Zone 5, Maximum (90–100%) from = round([B] + 0.9×([Maximum heart rate] – [B]))
- up to = round([B] + 1.0×([Maximum heart rate] – [B]))
Example values
How the main result changes when Age changes and everything else stays at the example values above:
| Age (years) | Maximum heart rate (bpm) |
|---|---|
| 17.5 | 203 |
| 26.25 | 194 |
| 35 | 185 |
| 43.75 | 176 |
| 52.5 | 168 |
| 70 | 150 |
Formula
With resting HR (Karvonen): target = RHR + % × (HRmax − RHR) · Without: target = % × HRmax · Zones 50–60, 60–70, 70–80, 80–90, 90–100%
Worked example
Inputs: Maximum heart rate formula: Fox – 220 − age; Age (years): 35; Do you know your resting heart rate?: Yes – use Karvonen; Resting heart rate (bpm): 65.
Results: Maximum heart rate = 185 bpm; Heart rate reserve = 120 bpm; Resting heart rate = Normal (60–100); Zone 1 – Very light (50–60%) from = 125 bpm; up to = 137 bpm; Zone 2 – Light / fat burning (60–70%) from = 137 bpm; up to = 149 bpm; Zone 3 – Moderate / aerobic (70–80%) from = 149 bpm; up to = 161 bpm; Zone 4 – Hard / anaerobic (80–90%) from = 161 bpm; up to = 173 bpm; Zone 5 – Maximum (90–100%) from = 173 bpm; up to = 185 bpm.
Key terms
- Karvonen method
- Zones based on heart rate reserve.
Frequently asked questions
What are heart rate zones?
Ranges of heart rate that target different training effects.
Which formula is best?
Tanaka or Gellish are more accurate than 220 − age for adults.
Why include resting heart rate?
Karvonen zones match fitness better than plain percentages.
How much time in each zone?
About 80% easy (zones 1–2), 20% hard (zones 4–5).
Sources
Guides on this topic
- Heart Rate Zones Explained: Max HR, Karvonen and the 80/20 Rule: Set your five heart rate zones from your own max and resting heart rate, see what each zone trains, and build a week around the 80/20 rule.