Tools
Heart Rate Zone Calculator
Find your five training zones three ways: from max heart rate, heart rate reserve, or lactate threshold.
Measure first thing in the morning, before getting up.
Your average heart rate over the last 20 minutes of a 30-minute all-out time trial.
| Zone | Heart Rate | Feels Like |
|---|
Different methods produce different zones — max HR is a rough starting point, threshold HR is the most training-relevant. When in doubt, the talk test wins: zone 2 means full sentences.
Enter your heart rate above to see your five training zones.
The short answer
Lactate threshold HR is the most training-relevant method — it anchors zones to a measurable physiological point. HR reserve (Karvonen) beats plain max-HR percentages by accounting for your resting HR. Max HR alone is the roughest estimate. Whichever method you use, the point is the same: keep easy days easy and hard days hard.
- Threshold HR: most accurate; max HR: roughest
- HR reserve (Karvonen) accounts for fitness via resting HR
- Retest every 8–12 weeks as fitness changes
Why do zones differ by method?
Most people land on this page hunting one number: their Zone 2 ceiling. Enter your numbers above with whichever method fits the data you have, and read it off the Zone 2 row of the results table. Every zone method is trying to divide the same thing — your range of effort — into useful slices. Max heart rate percentages are the simplest: 60–70% is zone 2, 90–100% is zone 5. But two runners with the same max can have very different fitness, and the method cannot see that.
Heart rate reserve (the Karvonen method) fixes this by subtracting resting heart rate first: zones become percentages of the range you actually use. A fitter runner with a lower resting HR gets zones that reflect their larger aerobic range.
Lactate threshold HR goes further — it anchors zones to the point where effort shifts from sustainable to unsustainable, which you can measure with a 30-minute time trial. For runners who train with structure, this is the method worth the trouble.
Whichever you use, remember what the zones are for: keeping easy days easy and hard days hard. The exact boundary between zone 2 and zone 3 matters less than the discipline of staying out of the grey middle on easy days.
Frequently asked questions
What are the five heart rate training zones?
Zone 1 (recovery, very easy), Zone 2 (aerobic base, easy and conversational), Zone 3 (tempo, comfortably hard), Zone 4 (threshold, hard but sustainable), and Zone 5 (VO2max, very hard intervals). Each zone trains a different energy system — which is why easy days and hard days should feel clearly different.
Which method is most accurate: max HR, HR reserve, or threshold?
Lactate threshold HR is the most training-relevant because it anchors zones to a measurable physiological point rather than an estimate. HR reserve (Karvonen) accounts for your fitness level via resting HR and beats plain max-HR percentages for most runners. Max HR alone is the roughest — fine as a starting point, not as a final answer.
Is 220 minus age accurate for max heart rate?
Not really — it is a population average with an error margin of 10–20 beats for individuals. A better estimate comes from a hard effort: your highest observed heart rate in a race finish or hill repeats. Lab testing is the gold standard, but observed max beats the formula for almost everyone.
What heart rate is zone 2?
Roughly 60–70% of max heart rate, or 60–70% of heart rate reserve — but the practical check is the talk test: you should be able to speak in full sentences. If the formulas and your breathing disagree, trust your breathing.
Can I use this calculator to find my Zone 2 heart rate?
Yes — that is the most common use. Enter your max, resting, or threshold heart rate above and read the Zone 2 row of the results table. The talk test still rules: if you cannot speak in full sentences at the top of the calculated range, train at the lower end.
How often should I retest my zones?
Every 8–12 weeks, or whenever your fitness clearly changes — easy pace dropping at the same heart rate is a sign your zones have shifted. Resting HR trending down over weeks is another signal that your aerobic base has grown and zones deserve a refresh.
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