Target Heart Rate Calculator

Your Target Heart Rate zones are the beats-per-minute ranges that let you train at exactly the right intensity for a given goal — burning fat, building endurance, improving cardiovascular fitness, or sharpening race pace. Runners, cyclists, rowers and gym-goers all use zones to make sure easy days stay easy and hard days actually go hard.

This calculator gives you the five classical zones based on your maximum heart rate (estimated from your age) and, if you enter it, your resting heart rate for more personalised bands.

How it works

We estimate your maximum heart rate (MHR) using the Tanaka formula:

• MHR ≈ 208 − (0.7 × age)

If you don't provide a resting heart rate we take simple percentages of MHR. If you do, we use the more accurate Karvonen formula, which works from your heart rate reserve (max minus resting):

• Target = RHR + intensity% × (MHR − RHR)

A worked example

A 40-year-old with a resting heart rate of 60 bpm has:
MHR = 208 − (0.7 × 40) = 180 bpm. Heart rate reserve = 180 − 60 = 120.
Zone 2 (60–70%) = 60 + (0.6 × 120) to 60 + (0.7 × 120) = 132 – 144 bpm. That's the sustainable, endurance-building pace where most easy runs and long rides should sit.

Why this matters

Most amateur athletes train too hard on easy days and too easy on hard days — ending up permanently in the "grey zone" that produces fatigue without much fitness. Genuine zone-based training separates the two, letting the body recover between hard efforts. The result is faster progress, lower injury risk and fewer plateaus.

Common mistakes

• Training every session in Zone 3 — hard enough to feel like effort, too light to drive real adaptation.
• Trusting a wrist-based heart rate reading during high-intensity intervals — chest straps are far more accurate.
• Using an estimated MHR when a proper field test would reveal a much higher or lower true maximum.
• Ignoring day-to-day variation caused by sleep, heat, illness or caffeine.
• Chasing "fat-burning zone" thinking it's the fastest route to weight loss.
• Pushing into Zone 5 without any base fitness or medical clearance.
• Not accounting for heart rate drift — long sessions in the heat can push heart rate up 5–10 bpm at the same effort.

Educational only — not a substitute for medical advice. If you have a heart condition, high blood pressure, are over 40 and new to exercise, or take medication that affects heart rate, speak to your GP before starting a training plan.

Related tools: BMR Calculator · Calorie Needs Calculator · Daily Water Intake Calculator · Body Fat Calculator