Heart Rate Zone Calculator
Estimate your maximum heart rate with the HUNT formula, see all five training zones in beats per minute, and get the exact work and recovery targets for the Norwegian 4x4 protocol. Signed in with a birth date on your profile? Your age is already filled in.
Your maximum heart rate
Enter your age (or a measured max) to see your zones.
Your five zones
| Zone | % of max | Beats per minute | Feels like |
|---|---|---|---|
| Z1 Easy | 50-60% | — | Warm-up and cool-down pace. You could sing. |
| Z2 Light | 60-70% | — | Conversational. Long easy sessions and 4x4 recoveries live here. |
| Z3 Moderate | 70-80% | — | Steady tempo. Full sentences are getting harder. |
| Z4 Hard | 80-90% | — | Hard. A few words at a time. Where the 4x4 build-up weeks start. |
| Z5 Max | 90-100% | — | Near max. The 4x4 work interval. Breathing dominates everything. |
Norwegian 4x4 targets
The protocol behind the 38-minute session: warm up, four 4-minute intervals at 90-95% of max with 3 minutes of active recovery between them, cool down. These are the numbers to hold on your watch.
- Warm-up and cool-down · 5 min each50-60%
- Work intervals · 4 × 4:0090-95%
- Active recovery · 3:00 after each round60-70%
Frequently asked questions
Formula reference: Nes BM, Janszky I, Wisløff U, et al. Age-predicted maximal heart rate in healthy subjects: the HUNT Fitness Study. Scand J Med Sci Sports. 2013;23(6):697-704. Zone targets for the Norwegian 4x4 follow norwegian4x4.com.