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Health & Fitness / Heart Rate Zone Calculator
OneFreePlace · Tool #145

Build heart-rate zones from the method you actually use.

Compare measured or age-predicted maximum heart rate, calculate five-zone %HRmax or heart-rate-reserve targets, switch to threshold-based running zones, inspect a live BPM, and keep the AHA moderate/vigorous ranges separate from sport-specific training zones.

✓ Measured / Tanaka / 220−age HRmax✓ %HRmax zones ✓ Karvonen / HRR zones✓ LTHR running zones ✓ Live BPM zone lookup
Heart Rate Zone Calculator
HRmax · HRR · LTHR · live lookup · AHA overlay
Athlete inputs

Choose the anchor before choosing the zones.

This adult calculator uses Tanaka’s equation from a large adult meta-analysis and cross-validation study. “220 − age” remains widely used, including by the American Heart Association, but both are estimates.
Zone systemChanging basis can materially change the BPM boundaries.
Live heart-rate lookupOptional. Enter a current/training BPM to see where it lands in the selected system and in AHA intensity guidance.
Default five-zone profile: 50–60%, 60–70%, 70–80%, 80–90%, 90–100% of HRmax, matching common Polar/Garmin defaults.
Selected zone system
Calculating
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maximum heart rate anchor
Enter valid heart-rate inputs.
Resting heart rate—used by HRR / Karvonen
Heart-rate reserve—HRmax − resting HR
AHA moderate range—about 50–70% of HRmax
AHA vigorous range—about 70–85% of HRmax
Live BPM zone—enter a BPM to classify it
Live intensity—AHA overlay + percentages
Training estimateAge-predicted HRmax and zone boundaries are guides, not diagnostic limits.

Your zones

Integer BPM ranges are made continuous with no display gaps. Underlying percentages remain visible so you can audit every boundary.

Formula comparison

Predicted maximum heart rate varies by equation. A measured maximum, when reliable and appropriate, is more individual than an age equation.

Zone-system comparison

See how the same 50/60/70/80/90/100 template shifts when it is based on HRmax versus heart-rate reserve.

Zone% band% HRmax% HRR / KarvonenDifference at lower edge

What the systems mean

% HRmaxSimple five-zone system used by Garmin and Polar defaults. Depends strongly on the HRmax anchor.
Simple
% HRR / KarvonenUses the reserve between resting and maximum HR, then adds resting HR back: resting + intensity × (max − resting).
Rest-aware
% LTHR runningThreshold-based endurance system. This tool uses Joe Friel’s published running bands: <85, 85–89, 90–94, 95–99, 100–102, 103–106, >106% LTHR.
Threshold-based

AHA intensity overlay

The American Heart Association describes moderate exercise as about 50–70% of maximum heart rate and vigorous exercise as about 70–85%. These are broad public-health intensity ranges, not the same thing as a sport-specific five- or seven-zone system.

Important limits

Age equations have individual errorTanaka’s adult equation is 208 − 0.7×age, but measured HRmax varies substantially around age-predicted values.
Estimate
Medication can change the responseThe AHA notes that some medicines can lower heart rate and change target ranges. Heart disease or prescribed exercise limits should override this calculator.
Clinical context
Symptoms matter more than the numberStop exercise and seek appropriate medical guidance for concerning chest pain, fainting, severe breathlessness or other alarming symptoms regardless of the calculated zone.
Safety
i
Use zones as training guides, not absolute safety limits.Wearable readings can lag or be inaccurate, formulas estimate populations, and medications or health conditions can change heart-rate response. If you have a heart condition, take heart-rate-affecting medication, or have been given a clinical exercise limit, use your healthcare professional’s target instead.