Age-based (220 − age, Tanaka, etc.)
- Accuracy
- ±10–30 bpm
- Who it's for
- Beginners, first-time HR trainers
- How long it takes
- 10 seconds
There are three ways to calculate your heart rate training zones. One is simple and inaccurate. One is moderately accurate but takes a hard test workout to set up. One is what I prefer for most runners, most of the time. This guide walks through all three — with worked examples — and tells you which one to use based on how serious you are about training by heart rate.
If you just want to skip the math and get your zones right now:
→ Calculate your 6 heart rate zones with the McMillan Heart Rate Zone Calculator
Otherwise, let’s build this from the ground up.
What Heart Rate Zones Are — And Why They Matter
Every run you do has a purpose. Recovery jogs, easy runs, tempo runs, threshold intervals, VO2max sessions — each one produces a different adaptation in your body. Heart rate zones are a reliable way to make sure you’re actually training the system each workout is designed to train.
Zones work because your heart rate corresponds predictably to how hard your body is working. An easy conversational run sits in one band. A tempo run at “comfortably hard” effort sits in a higher band. VO2max intervals push near your maximum. If your zones are calculated correctly, your heart rate monitor becomes a real-time gauge that keeps each workout honest.
The problem is that calculating zones badly is worse than not using them at all. If your “easy” zone is actually too high, you’ll run every easy day too hard and never recover. If your “threshold” zone is too low, your tempo workouts will feel great but produce nothing. Getting the math right matters.
The 3 Methods at a Glance
The three methods for calculating heart rate zones, ranked from least to most accurate.
Lactate Threshold (LTHR)
- Accuracy
- Moderate. More accurate than age-based, less accurate than HRR with a measured max HR.
- Who it's for
- Runners who don't want to do a max-effort field test
- How long it takes
- A 30-min time trial workout
Heart Rate Reserve (Karvonen) with measured max HR
- Accuracy
- Best — personalized to your resting HR and tested max HR
- Who it's for
- Most runners, most of the time
- How long it takes
- 5 minutes + morning resting HR log + a max HR field test
Method 1: Age-Based Formulas (Simple, Least Accurate)
Age-based formulas use your age to estimate your maximum heart rate, then calculate your zones as percentages of that number. The most famous is Fox/Haskell: Max HR = 220 − age. More accurate variants exist — Tanaka (208 − 0.7 × age) tends to be closer for masters runners, and the Gulati formula (206 − 0.88 × age) was developed specifically for women.
How to calculate:
- Estimate your max HR using one of the formulas
- Multiply by the zone percentage to get your zone range
For a 40-year-old using the 220-age formula, max HR is 180. Zone 2 (easy running) at 60–75% of max would be 108–135 bpm.
Nerdy note — the four formulas, side by side
If you want a quick read on what each formula gets right and wrong, here’s the short version:
- Fox/Haskell (220 − age): Easy to remember. Comes from a 1971 paper that wasn’t designed as a training tool. Off by 10–30 bpm for any individual.
- Tanaka (208 − 0.7 × age): From a 2001 meta-analysis of 351 studies. More accurate than 220-age, especially for masters runners.
- Gulati (206 − 0.88 × age): Developed in 2010 for women specifically, from data on 5,000+ healthy female subjects. Addresses the male bias in older formulas.
- Nes (211 − 0.64 × age): From a 2012 Norwegian study of 3,000+ healthy adults. Among the most accurate age-based formulas in independent validation.
Full breakdown of all four, with the field-test alternative I actually recommend, lives in the Max Heart Rate Calculator post.
Why I don’t recommend age-based formulas as your primary method
The most commonly used formula — 220-minus-your-age — can be off by 10 to 30 beats per minute for any given individual. That’s not a small error. Thirty beats is the difference between Zone 2 and Zone 5. If your real max HR is 190 but the formula says 180, every training zone you calculate will be too low, and you’ll end up training every system at the wrong intensity.
Age-based formulas are fine as a rough starting estimate if you’re new to HR training and want to get running today. They’ll put you in the neighborhood. But they’re not accurate enough to build serious training around — and they get worse the further your real max HR is from the population average.
For the field test I actually recommend, see the Max Heart Rate Calculator post.
Method 2: Lactate Threshold Heart Rate Method
Instead of anchoring your zones to your max HR, this method anchors them to your lactate threshold heart rate (LTHR) — the highest heart rate you can sustain for about an hour.
LTHR-based zones are more accurate than age-based formulas because they’re built on a number you actually measured rather than one a formula guessed. The trade-off: LTHR introduces some error of its own (it requires giving genuine race effort for 30 minutes, which most runners don’t pace perfectly), and it’s still less accurate than the heart rate reserve method when you have a properly measured max HR.
The reason some runners prefer LTHR over the max HR field test is simple — LTHR doesn’t require an all-out maximal effort. A 30-minute time trial is hard, but it’s not the same as pushing your heart rate to its absolute ceiling on a hill. If you’ve got a cardiac concern that makes max-effort testing unwise, or you just don’t want to red-line, LTHR is a reasonable middle path.
How to find your LTHR: the 30-minute time trial
The most widely accepted protocol is Joe Friel’s 30-minute time trial test. Run the test when you’re rested, well-fueled, and able to give genuine race effort:
- Warm up thoroughly for 10–15 minutes with some faster strides
- Run a 30-minute time trial at the fastest pace you can sustain for the full 30 minutes. Go by effort, not by pace target
- Ten minutes into the time trial, start tracking your average heart rate for the remaining 20 minutes
- That average HR across the final 20 minutes is your LTHR
The reason we ignore the first 10 minutes: your HR is still climbing as your body ramps up. By 10 minutes in, you’ve reached the steady state that represents your real sustainable threshold effort.
Cool down with 10 minutes of easy jogging afterward. This test is hard — treat it like a race. Don’t plan a workout the day after.
Using LTHR to build your zones (Friel’s 5-zone framework)
Once you have your LTHR, zones are calculated as percentages of it:
- Zone 1: below 68% LTHR
- Zone 2: 68–83% LTHR
- Zone 3: 84–94% LTHR
- Zone 4: 95–105% LTHR (this is your threshold zone)
- Zone 5: above 106% LTHR
These percentages reflect Friel’s framework, which uses 5 zones for LTHR-based calculations. The McMillan 6-zone system uses HRR — see Method 3. If you’re training with the McMillan system, the McMillan calculator (HRR-based with a measured max HR) is the preferred method. LTHR-based zones are useful if max-effort testing isn’t an option for you.
When LTHR testing makes sense
If you’ve got 6+ months of consistent base, want better-than-formula accuracy, and don’t want to do a max-effort field test, LTHR is a perfectly good way to anchor your zones. Just know it’s not as accurate as the McMillan HRR method when you’ve measured your real max HR.
Method 3: Heart Rate Reserve / Karvonen (My Preferred Method)
This is the method I prefer for most runners, most of the time — and it’s what the McMillan Heart Rate Zone Calculator uses.
Heart Rate Reserve (HRR) accounts for both your max HR and your resting HR, giving you zones that are personalized to your actual cardiovascular profile. The formula:
HRR = Max HR − Resting HR
Target HR = (HRR × zone %) + Resting HR
How to calculate:
- Find your max HR — ideally from a field test (see Max Heart Rate Calculator for the McMillan Field Test protocol). Use an age-based formula as a starting estimate if you haven’t tested yet.
- Measure your resting HR first thing in the morning, before you get out of bed. Count for 30 seconds and multiply by 2. Do this for several mornings and take the average.
- Plug both numbers into the formula above for each zone.
Why HRR beats straight age-based percentages
If two runners both have a max HR of 185, but one has a resting HR of 45 (highly trained) and the other has a resting HR of 70 (less trained), their easy-run zones should be different. HRR captures that. A straight percentage of max HR does not.
In practice this is a meaningful difference. The same 40-year-old with a measured max HR of 185 and a resting HR of 50 gets a Zone 2 range of 124–155 bpm using HRR — versus 111–139 bpm using plain percentages of max HR. That’s 15 beats higher at the top of Zone 2, which much more accurately reflects the effort a trained runner actually experiences on a conversational run.
The McMillan 6 HR zones (using HRR)
- Zone 1 — Recovery jogs: 55–65% HRR
- Zone 2 — Easy and long runs: 55–78% HRR
- Zone 3 — Early threshold / steady state: 75–80% HRR
- Zone 4 — Lactate threshold: 80–85% HRR
- Zone 5 — High threshold / cruise intervals: 82–87% HRR
- Zone 6 — Speed and sprint workouts: 90–100% HRR
Six zones instead of five because lactate threshold training needs more precision than most systems give it — some workouts sit slightly below threshold, some right at it, and some slightly above. Splitting threshold into three zones gives you the resolution that matters for getting faster.
For a runner’s-eye walkthrough of what each zone feels like and the workouts that belong in it, see Running Heart Rate Zones. For a deep dive on Zone 2 specifically — the aerobic base that everything else gets built on — see the Zone 2 Heart Rate Calculator post.
→ Calculate your 6 zones with the McMillan Calculator Free. No signup.
Worked Example: A 40-Year-Old Runner
Meet Sarah. She’s 40, she’s been running 4–5 days a week for a year, and she wants to set up her heart rate zones properly.
Step 1 — Max HR: Sarah runs a field test and hits 185 bpm. (Her age-based estimate would have been 180 using 220-age, or 180 using Tanaka — close, but a real measurement is better.) See Max Heart Rate Calculator for the field test protocol.
Step 2 — Resting HR: For a week of mornings, Sarah counts her pulse before getting out of bed. She averages 52 bpm.
Step 3 — Heart Rate Reserve: HRR = 185 − 52 = 133.
Step 4 — Calculate zones using HRR:
- Zone 1 (recovery): (133 × 0.55) + 52 = 125 bpm → (133 × 0.65) + 52 = 138 bpm
- Zone 2 (easy/long): 125 → (133 × 0.78) + 52 = 156 bpm
- Zone 3 (steady state): (133 × 0.75) + 52 = 152 → (133 × 0.80) + 52 = 158
- Zone 4 (lactate threshold): 158 → (133 × 0.85) + 52 = 165
- Zone 5 (cruise intervals): (133 × 0.82) + 52 = 161 → (133 × 0.87) + 52 = 168
- Zone 6 (speed/sprint): (133 × 0.90) + 52 = 172 → 185
What Sarah does with this:
Her easy runs stay in Zone 2 (125–156 bpm). Her tempo runs target Zone 4 (158–165). Her interval workouts hit Zone 6. When she sees her HR creeping to 160 on what was supposed to be an easy run, she knows to slow down — the monitor is telling her she’s drifting into steady-state territory.
Or she could do all this math in 30 seconds using the McMillan calculator. That’s what it’s for.
Which Method Should You Use?
New to heart rate training: Start with age-based (Method 1) to get running today. Graduate to HRR (Method 3) within a few weeks.
Serious recreational runner: Use HRR (Method 3) with a field-tested max HR. This is the method the McMillan calculator uses, and it’s the most accurate option for the vast majority of runners.
Can’t or don’t want to do a max-effort field test: Use LTHR (Method 2). Less accurate than HRR with a tested max, but better than relying on a formula alone.
Racing or training at a high level: Use HRR with a tested max HR. Re-test your max HR yearly and at the start of each new training cycle. Recalculate your resting HR and zones whenever your fitness shifts meaningfully.
For almost everyone reading this, the answer is Method 3 — Heart Rate Reserve with a measured max HR — and the McMillan calculator does the arithmetic for you.
→ Calculate your zones now with the McMillan Heart Rate Zone Calculator
Frequently Asked Questions
For most runners, the Heart Rate Reserve (Karvonen) method using a field-tested max HR is the most accurate option. It accounts for both your max HR and your resting HR, giving you more personalized zones than straight percentages of max HR.
The McMillan system uses 6 zones because lactate threshold training needs more precision than the typical 5-zone systems provide. Breaking threshold into three zones (slightly below, at, and slightly above) lets you target specific threshold adaptations with more control.
Yes. You can take your pulse manually, but it drops fast the moment you stop running and most runners can’t multi-task enough to count beats mid-run. A chest strap or wrist-based monitor gives you continuous, real-time feedback that actually lets you adjust pace during a workout. Most modern smartwatches include heart rate measurement, so the watch you already own probably already provides it.
At least once a year — and before any new training cycle. Resting HR drops as you get fitter, which shifts your HRR zones. Max HR changes gradually with age. A fresh calculation at the start of each training block keeps your zones honest with where your body actually is.
No. Your running max HR is typically 5–10 bpm higher than your cycling max HR because running recruits more muscle mass. If you train in both sports, calculate each sport’s zones separately using sport-specific max HR or LTHR values.
That’s normal and expected — the formulas are population averages, and individual variation of 10–30 bpm is common. This is the main reason we recommend either a field test (for max HR) or a time trial test (for LTHR) over pure-formula-based zones. Your body’s numbers are your body’s numbers, not the average’s.
Related Reading
- McMillan Heart Rate Zone Calculator — The tool. HRR-based, 6 personalized zones, free
- Max Heart Rate Calculator — Deep dive on max HR: four formulas, the McMillan Field Test, worked examples
- Zone 2 Heart Rate Calculator — Everything you need to know about the Zone 2 aerobic training zone
- Running Heart Rate Zones — How each zone feels when you’re running and what workouts to do there
Written By Greg McMillan
Called “one of the best and smartest distance running coaches in America” by Runner’s World’s Amby Burfoot, Greg McMillan is renowned for his ability to combine the science of endurance performance with the art of real-world coaching. While getting his graduate degree in Exercise Science he created the ever-popular McMillan Running Calculator – called “The Best Running Calculator” by Outside Magazine. A National Champion runner himself, Greg coaches runners from beginners to Boston Qualifiers (15,000+ and counting!) to Olympians.
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