Heart rate zone calculator
Your five training zones — where easy should actually be, and where hard starts counting.
Estimated max heart rate
190bpm
Zones as % of max — add your resting HR for the more personal Karvonen method
| Zone | Range | What it's for |
|---|---|---|
| Z1 · Recovery | 95–114 | Easy movement — warm-ups and active recovery |
| Z2 · Endurance | 114–133 | All-day aerobic pace — the famous zone 2 |
| Z3 · Tempo | 133–152 | Comfortably hard — conversation comes in fragments |
| Z4 · Threshold | 152–171 | Sustainable for roughly 20–60 minutes |
| Z5 · VO2 max | 171–190 | Short, hard intervals only |
How the zones are built
Max heart rate is estimated as 220 minus age, and the five zones split the range at 50–60–70–80–90–100%: recovery, endurance, tempo, threshold and VO2 max. Add your resting heart rate and the calculator upgrades to the Karvonen method, anchoring each zone to your heart rate reserve instead — the same percentages, personalized floors.
The practical split most coaches prescribe: around 80% of cardio time in zones 1–2 and the rest in 4–5, with zone 3 as the comfortable-but-unproductive middle you mostly pass through. Easy days easy, hard days hard — the zones just make both honest.
Frequently asked questions
What is zone 2 and why does everyone talk about it?
Zone 2 is the easy aerobic range — roughly 60–70% of max heart rate, a pace where you can hold a conversation. It builds mitochondrial density and aerobic base with minimal recovery cost, which is why endurance coaches have athletes spend most of their time there and why it went from insider practice to podcast obsession. The catch: done honestly, it feels almost too easy.
How accurate is the 220-minus-age formula?
It's a population average with a spread of ±10–12 beats — plenty of 40-year-olds have true maxes of 195, others 165. Zones built from it are a solid starting point, but if training by heart rate becomes central for you, a field test (like the average of the last 20 minutes of an all-out 30-minute effort) beats any formula.
What does adding my resting heart rate change?
It switches the math to the Karvonen method, which computes zones as a fraction of your heart rate reserve — the span between resting and max — rather than a fraction of max alone. Two people with the same max but resting rates of 48 and 75 have very different engines; Karvonen's zone floors reflect that, and they rise naturally as your fitness improves and resting HR drops.
Should I train by heart rate or by feel?
Both, in that order of learning. Heart rate teaches you what each zone actually feels like — nearly everyone's 'easy' is zone 3 until a monitor proves otherwise. After a few months the feel is calibrated and the strap becomes a spot check. Heart rate lags effort by a minute or two, so for short intervals go by pace or power and use HR for the steady work.
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