Five training zones with direct-%max comparison markers Updates with every input
Health & Fitness
Heart Rate Zone Estimate Calculator
Estimate five training zones from age, resting heart rate, an optional measured maximum, and chosen intensity boundaries while comparing age-based maximum-heart-rate methods and heart-rate-reserve targets.
Selected estimated maximum —
Tanaka age estimate —
Fox age estimate —
Heart-rate reserve —
Moderate HRR range —
Vigorous HRR range —
Tanaka–Fox difference —
Method interpretation —
Heart-rate reserve arc
Five training zones with direct-%max comparison markers
Concentric colored arcs use heart-rate reserve; small markers show where direct percentages of maximum would land.
Zone prescription table
Five editable intensity bands using two calculation methods
Heart-rate-reserve ranges include resting heart rate; direct-percent ranges do not. The difference is shown rather than hidden.
| Zone | Intensity band | HRR method | % maximum method | Midpoint difference | Typical planning label |
|---|
Zone setup
Select the maximum-HR evidence before reading the zones
- Use a resting heart rate measured in a calm, consistent condition.
- Leave measured maximum at zero unless it comes from an appropriate maximal test.
- Choose Tanaka, Fox, or measured mode explicitly.
- Set increasing zone boundaries; the calculator corrects crossed boundaries to preserve order.
- Compare the HRR and direct-percent columns instead of assuming they are interchangeable.
Estimation limits
Age equations describe group averages, not an individual's true maximum
Tanaka's equation was derived from a meta-analysis and laboratory cross-validation, but later research still found wide individual error around age-predicted maximum heart rate. The page therefore displays method difference and permits a measured value.
Heart-rate reserve includes resting heart rate and often yields different targets from multiplying maximum heart rate directly. Medication, heat, fatigue, illness, and sensor error can also change the observed response.
Zone estimation method
Estimate maximum heart rate, then apply heart-rate reserve
Tanaka estimates maximum as 208 − 0.7 × age; Fox uses 220 − age. If a valid measured maximum is selected, it replaces the age estimate. Each zone then adds a percentage of heart-rate reserve back to resting heart rate.
Detailed calculation process and general formulas
HRmax_Tanaka = 208 − 0.7 × ageHRmax_Fox = 220 − ageHRmax_selected = chosen estimate or measured HRmaxHRR = HRmax_selected − HRrestHR_target(p) = HRrest + p × HRRSymbols, meanings, and units
- HRmax_Tanaka, HRmax_Fox
- age-predicted maximum heart ratesbpm
- HRmax_selected
- maximum used for the zone calculationbpm
- HRrest
- entered resting heart ratebpm
- HRR
- heart-rate reservebpm
- p
- fractional training intensitydecimal
Method comparison
Three evidence levels for maximum heart rate
Choose the strongest appropriate input; do not treat a calculated maximum as a measured physiological ceiling.
Tanaka estimate
—208 − 0.7 × age; used as the default age-based method.
Fox estimate
—220 − age; retained because it remains widely recognized.
Measured maximum
Use only when obtained from a suitable test and interpreted appropriately.
Decision takeaway: Use zones as flexible training guides and combine them with perceived effort, symptoms, and professional advice.
Better zone evidence
What improves confidence in the estimate
- Consistent resting-HR measurement
- Appropriate maximal or threshold testing
- Validated sensor data
- Medication review
- Perceived exertion and talk-test notes
Applied decisions
Zone decisions that benefit from method comparison
Forty-year-old with a 62 bpm resting rate
Tanaka and Fox maximum estimates are close, but HRR targets sit above direct-%max targets at lower intensities.
What the result clarifies: The table exposes the method difference for every zone.
Athlete with a tested maximum
A valid measured maximum differs from both age estimates.
What the result clarifies: Measured mode updates all arcs while preserving the same editable intensity boundaries.
Worked default scenario
Current-input substitution and reconciliation
Method references
Evidence used to frame the model
Scope and limitations
This calculator is not a medical exercise clearance tool. Age-predicted maximum heart rate has substantial individual error. Heart conditions, symptoms, pregnancy, medications such as beta blockers, and clinician-directed rehabilitation require individualized exercise guidance. Stop exercise and seek appropriate care for concerning symptoms.
Heart Rate Zone Estimate Calculator | Tanaka, Fox, and Heart-Rate Reserve FAQ
Why do HRR and percent-maximum zones differ?
HRR subtracts resting heart rate before applying intensity and then adds it back.
Which age formula is exact?
Neither. Both are population estimates with meaningful individual error.
Can a wearable provide measured maximum?
A device-recorded peak is not automatically a validated maximal test; review context and data quality.
Do medications affect target heart rate?
Yes. Some medications alter heart-rate response, so clinician-directed targets may be needed.