Heart Rate Zones

Training zones from age and resting heart rate (Karvonen)

Heart Rate Zones is a free online browser-based utility designed to training zones from age and resting heart rate (karvonen). All computations, processing, and rendering happen completely inside your browser client, ensuring your data is kept secure and private.

How to use Heart Rate Zones

  1. Enter Inputs. Input your data, values, or upload your file into the provided container panel.
  2. Configure Options. Adjust sliders, selectors, or toggles to customize your desired output parameters.
  3. Verify Live Preview. Review the instant calculation or visual representation generated in real-time.
  4. Export Result. Click the Copy or Download button to save your formatted output.

Features

  • Clean Interface: Streamlined layout designed for maximum focus and efficiency.
  • One-Click Copy/Download: Easily export results to your clipboard or local files.
  • Offline Ready: Works without an internet connection once loaded in your browser.

Why use this tool

  • 100% Privacy: All processing happens locally in your browser. No files or inputs are sent to any servers.
  • Lightning Fast: Instant client-side calculations with zero network latency or server load times.
  • Mobile Responsive: Designed to work flawlessly on smartphones, tablets, and desktop browsers.

Frequently asked questions

How do I calculate my heart rate zones?

This tool uses the Karvonen method: max heart rate = 220 - age, reserve = max - resting rate, and each zone = resting + reserve x a percentage. For age 30 and resting 60, max is 190, reserve 130, and Zone 2 (60 to 70%) is 138 to 151 bpm.

What is the Karvonen formula?

Karvonen sets target heart rate as resting heart rate + (max heart rate - resting heart rate) x intensity. It personalises zones using your resting pulse, so two people the same age get different zones if their resting rates differ.

What are the five heart rate zones?

The tool shows Zone 1 (50 to 60% of reserve, very light), Zone 2 (60 to 70%, endurance), Zone 3 (70 to 80%, aerobic), Zone 4 (80 to 90%, threshold) and Zone 5 (90 to 100%, maximum). For age 30 and resting 60, Zone 3 is 151 to 164 bpm.

How do I measure my resting heart rate?

Check it first thing in the morning, before getting up or having caffeine. Find your pulse at the wrist or neck, count beats for 30 seconds and double it, and average a few days. Many adults fall somewhere between 60 and 100 bpm, but it varies.

Is 220 minus age an accurate maximum heart rate?

It is a rough population estimate, and real maximums vary by many beats either way between individuals. Other formulas exist. Use the zones as a guide, and if you need an exact figure, a supervised test with a professional is more reliable.

Is it safe to train in the higher heart rate zones?

That depends on your health. Zones 4 and 5 are hard efforts. This is general information, not medical advice; see a doctor before starting intense training, especially if you have heart or blood pressure concerns, are new to exercise or take medication.

Is my data shared when using the Heart Rate Zones?

No. Toolskyt operates under a zero-server policy. All calculations, data formatting, and file exports are executed locally on your machine.

Do I need to sign up or pay to use the Heart Rate Zones?

No, this tool is 100% free. There are no limits, sign-ups, subscriptions, or hidden charges required.

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