Heart Rate Zone Calculator for Runners

Very light effort. Used for warm-ups, cool-downs, and active recovery between hard sessions. Builds capillary density and teaches your body to burn fat efficiently. Most of your running should feel this easy.

Comfortable, conversational pace. This is where you build endurance and aerobic capacity. You can talk in full sentences. 60–70% of your weekly volume should be in Zone 2. The "easy run" zone.

Comfortably hard. You can speak in short phrases but not hold a conversation. Marathon and half-marathon race pace often falls here. Improves lactate clearance and muscular endurance.

Hard effort at or near your lactate threshold. Sustainable for 20–60 minutes in trained runners. Tempo runs, cruise intervals, and 10K–15K race pace. Raises your anaerobic threshold.

Near-maximal effort. Sustainable for only 3–8 minutes. Used in short, hard intervals (e.g. 5×1000m). Develops maximal oxygen uptake and neuromuscular power. Very taxing — limit to 1–2 sessions per week.

The simplest estimate: 220 minus your age. Quick but imprecise — individual variation can be ±10–15 bpm. A 35-year-old gets 185 bpm, but their real max could be anywhere from 170 to 200.

Warm up for 10–15 minutes. Run 3×800m at maximum effort with 2 min recovery. The highest HR in the final interval is close to your max. Best done on a track, fully rested, and in good health.

Check your max HR from a hard 5K or 10K race. The peak HR from an all-out race is a reliable indicator, especially if you sprinted the last 400m. Your sports watch records this automatically.

Which method should I use — Max HR, LTHR, or Karvonen?

If you only know your age, start with Max HR. If you have done a lactate threshold test or a hard 30-minute time trial, LTHR is more accurate for training. Karvonen (Heart Rate Reserve) accounts for your resting HR and is the most individualized — use it if you know both your max and resting HR.

How accurate is the 220 − age formula?

It's a rough estimate with ±10–15 bpm error. Some 40-year-olds have a max HR of 195, others 170. For precise zones, do a field test or use race data. The formula is a starting point, not a final answer.

Should I train by heart rate or by pace?

Both are useful. Heart rate reflects internal effort — it adjusts for heat, fatigue, hills, and stress. Pace reflects external output. Use HR for easy and recovery runs (to avoid going too fast), and pace for intervals and tempo (where HR lag makes it less responsive).

What if my HR zones don't match my pace zones?

This is normal. HR zones and pace zones are different systems. Your easy pace zone might put you in Zone 2–3 by HR, especially on hilly terrain or hot days. Use HR as a guardrail for effort, and pace as a target for structured workouts. Over time, the same pace will produce a lower HR — that's fitness improving.