Target Heart Rate Calculator — Free Heart Rate Zone Tool

Target Heart Rate Calculator — Free Heart Rate Zone Tool. Free target heart rate calculator using the Karvonen formula (% of heart-rate reserve). Find your max heart rate and heart rate zones for fat burn, aerobic, and anaerobic training.

Our free target heart rate calculator uses the Karvonen formula to compute your personal heart rate training zones in seconds.

Enter your age and resting heart rate to instantly see your max heart rate calculator result alongside five precision zones — Warm-Up, Fat Burn, Aerobic, Anaerobic, and Red Line.

Unlike simple 220-minus-age tools, the Karvonen method factors in your resting heart rate (Heart Rate Reserve) for zones that are genuinely calibrated to your cardiovascular fitness level, not just your age.

The heart rate zone calculator output shows the exact beats-per-minute range for each training intensity, so you can match your workout effort to your goal — whether that's easy steady work in the fat-burn zone (60–70% of heart-rate reserve, HRR), endurance in the aerobic zone (70–80% HRR), or speed development in the anaerobic zone (80–90% HRR).

Each percentage is applied to your heart-rate reserve (max heart rate minus resting heart rate) and then added back to your resting heart rate, as the Karvonen formula requires — it is not a percentage of max heart rate.

Everything runs locally in your browser; your age and resting heart rate are never sent to any server, making this a fully private karvonen heart rate calculator with zero data exposure.

The tool also doubles as a max heart rate calculator: it displays your estimated MHR (220 – age) at the top of the results, so you get both the ceiling figure and the zone breakdown in one screen.

Pair it with the TDEE Calculator or BMR Calculator on this platform to build a complete fitness and nutrition profile.

Bookmark this page for an always-available, offline-capable fat burning heart rate calculator that works without an internet connection once loaded.

Frequently asked questions

How do I calculate my target heart rate zones?

Type your Age and Resting Heart Rate (30 and 60 by default). The page shows your estimated Max Heart Rate and a table of five zones, Warm Up, Fat Burn, Aerobic, Anaerobic and Red Line, each with a beats-per-minute range. Results update as you type; there is no button to press.

What formula does this heart rate zone calculator use?

Max heart rate is estimated as 220 minus your age. Each zone uses the Karvonen formula: target = (max heart rate - resting heart rate) x intensity + resting heart rate. The zone percentages are therefore percentages of your heart rate reserve, not of max heart rate.

What are the five heart rate zones?

Warm Up is 50 to 60 percent, Fat Burn 60 to 70, Aerobic 70 to 80, Anaerobic 80 to 90 and Red Line 90 to 100 percent of your heart rate reserve. Lower zones suit easy, longer sessions and higher zones short, hard efforts.

How do I measure my resting heart rate?

Count your pulse for a full minute while sitting or lying still, ideally just after waking up, or use the resting value from a fitness watch. Entering your real resting rate makes the zones more personal than formulas based on age alone.

Is this target heart rate calculator medical advice?

No. The results are estimates, not medical advice. The 220 minus age formula is a population average and your real maximum can differ considerably. If you have a heart condition or high blood pressure, or take medication that affects heart rate, ask a doctor before training by these numbers.

Are my age and heart rate saved or uploaded?

No. The zones are calculated in your browser and the numbers you enter are not sent to a server or stored.

How to use this online tool

Target Heart Rate Calculator — Free Heart Rate Zone Tool is designed for fast browser workflows when you need to format, validate, convert, decode, encode, generate, or inspect data without opening a heavy desktop app. Start with the input field or visible options, review the result, then copy or download the output for the next step.

Private processing in your browser

Target Heart Rate Calculator — Free Heart Rate Zone Tool keeps the normal processing step local in your browser. That is useful for code snippets, tokens, documents, configuration values, text samples, and other material that should not be sent to a remote service unless you explicitly choose to share it.

When this tool is useful

Use Target Heart Rate Calculator — Free Heart Rate Zone Tool for repeatable developer tasks, technical documentation, QA checks, quick conversions, debugging, content cleanup, and internal team workflows. The page focuses on clear inputs, immediate feedback, and output that is easy to reuse in code, reports, tickets, emails, or notes.

Practical tips

Before copying the final result, check important details such as spacing, casing, filenames, encoding, token structure, line breaks, or output format. Small checks prevent mistakes when the result is reused in source code, API requests, documentation, spreadsheets, or shared files.