Which is better: Max% or Karvonen?

Karvonen (HRR) personalises zones using resting HR and can be more accurate for individuals with unusually low or high resting HR. Max% is simpler and widely used.

How accurate are Max HR formulas?

They are population averages and can be off by ±10–15 bpm for an individual. Use a measured max if possible.

Do zones change with fitness?

Yes. Resting HR can drop with training, altering HRR‑based zones. Re‑check every few months.

Calculator

Heart‑rate zones.

Enter your age (and resting HR if using Karvonen) to compute zones 1–5 for training. Includes examples, zone descriptions, and FAQs.

Calculate your zones

Age (years)

Max HR (optional)

If blank, Max HR is estimated via Tanaka. You can override it here.

Training zones

Zone	Intensity	Range (bpm)	% range
1	Easy / Recovery	—	50–60%
2	Endurance / Aerobic	—	60–70%
3	Tempo / Moderate	—	70–80%
4	Threshold / Hard	—	80–90%
5	VO₂ / Very hard	—	90–100%

Max% vs Karvonen (HRR)

Max% method scales each zone directly off your estimated or measured maximum heart‑rate. Karvonen (Heart‑Rate Reserve) uses the difference between max and resting HR (HRR = Max − Resting) and then adds your resting HR back to get target zone BPM. HRR often better reflects individual differences in resting heart‑rate.

Worked examples

Examples are rounded to whole beats.
Inputs	Method	Zone 2 (60–70%)	Zone 4 (80–90%)
Age 40 (Tanaka ⇒ Max≈180)	Max%	108–126 bpm	144–162 bpm
Age 40, Rest 60 (Tanaka Max≈180)	Karvonen	132–144 bpm	156–168 bpm

Limitations & tips

Max HR formulas are averages; your measured max may differ by ±10–15 bpm.
Use perceived exertion (RPE) and pace alongside HR, especially in heat or on hills.
Re‑measure resting HR after consistent sleep and low stress for accurate HRR.

Related tools

How to use your zones

Enter your age (and resting HR if using HRR) to get zone ranges. Use Zone 2 for easy aerobic base, Zone 3 for sustained tempo, Zone 4 near lactate threshold, and Zone 5 for short VO₂ intervals. Mix zones across the week and recover well.

How the heart-rate formulas compare

The calculator estimates your training zones by pairing a maximum heart-rate model with either a straight percentage (Max%) or the Karvonen Heart-Rate Reserve method. If you provide a measured max HR the formulas adapt automatically.

Max HR estimation

Formula	Expression	Pluses	Minuses
Tanaka et al.	Max HR = 208 − 0.7 × age	Validated on a large mixed-age cohort; slightly lower error for masters athletes.	Still an average — individual variation ±10–15 bpm is common.
Fox "220 − age"	Max HR = 220 − age	Easy to remember, historically widespread in fitness materials.	Overestimates for older adults and underestimates for younger runners more often than Tanaka.
Custom	Max HR = your lab/field-tested value	Removes model error when you know your true maximum.	Requires an all-out test; risky without supervision and can change with detraining.

Zone calculation methods

Method	Core formula	When it shines	Watch-outs
Max%	Zone range = Max HR × target %	Simple group coaching, when resting HR is typical (≈60–70 bpm) and you just need quick zones.	Ignores individual differences in resting HR; athletes with very low resting HRs can get ranges that feel too easy.
Karvonen (HRR)	Target HR = Resting HR + (Max − Resting) × %	When you track resting HR and want zones that scale to your aerobic fitness and recovery status.	Requires reliable resting HR data and shifts if you’re fatigued or ill.

Regardless of method, zone boundaries are rounded to whole beats. Check perceived effort and pace against these numbers—especially in heat, humidity, or on hills—to ensure the training effect matches your plan.