Free Tool

HEART RATE ZONE CALCULATOR

Enter your max heart rate or LTHR and get your 5 training zones.

YOUR MAX HEART RATE (BPM)

Don't know? Try 220 minus your age as a starting estimate.

METHODOLOGY

Max HR method: Zones are calculated as percentages of maximum heart rate using the 5-zone model widely adopted in cycling coaching. Zone boundaries at 60%, 70%, 80%, and 90% of max HR.

LTHR method:Zones are calculated from lactate threshold heart rate using Joe Friel's methodology from The Cyclist's Training Bible. LTHR-based zones are more accurate because they reflect fitness, not just genetics.

Limitations: Heart rate varies with fatigue, heat, caffeine, sleep, and stress. Power-based training zones (from FTP) are more consistent for interval targeting. Heart rate remains useful for pacing easy rides and monitoring recovery.

Last updated: April 2026 · Tool version 1.0

Quick answer

Enter either Max HR or Lactate Threshold HR (LTHR). The tool returns your five training zones in beats per minute — Active Recovery, Endurance, Tempo, Threshold, and VO2 — using the established Friel-style percentage bands.

WHAT IT DOES

Heart rate is the cheapest, most universal training signal. This calculator turns one number — either Max HR or LTHR — into five zone ranges you can dial straight into your Garmin, Wahoo, or Polar device.

WHO IT'S FOR

→Riders training without a power meter
→Cyclists who use HR as a backup to power
→Beginners getting structured for the first time
→Anyone setting up a new device or platform

HOW IT WORKS

If you enter LTHR, we use Friel's zone bands as percentages of LTHR — slightly more accurate than Max HR for trained athletes. If you only have Max HR, we apply Karvonen-style percentages of HRmax. LTHR comes from the average HR for the last 20 minutes of an FTP test; Max HR comes from a true all-out 5-min effort or a recent strenuous race.

01
Pick which number you have
LTHR (preferred for trained riders) or Max HR. If neither, do a 20-minute FTP test and record both — average HR for the last 20 min is your LTHR estimate; the highest reading is close to Max HR.
02
Enter the value
LTHR typically falls 130-180 bpm for adults; Max HR typically 170-200 bpm. Outside these ranges is possible but rare.
03
Read the five zones
Z1 (recovery), Z2 (endurance), Z3 (tempo), Z4 (threshold), Z5 (VO2).
04
Apply on the bike
Use the zones as a target on outdoor rides where power isn't available, or as a sanity check on indoor sessions. Heart rate drifts upward 5-10 bpm after 60 minutes — that's normal cardiac drift, not a fitness problem.

EXAMPLE CALCULATIONS

Trained rider with LTHR test

· LTHR: 168 bpm

Z2: 119-141 bpm. Z3: 142-159 bpm. Z4: 160-176 bpm. Z5: 177+ bpm.

New rider with Max HR estimate

· Max HR: 188 bpm

Z2: 113-141 bpm. Z3: 142-160 bpm. Z4: 161-179 bpm.

LIMITATIONS

Heart rate is influenced by sleep, caffeine, dehydration, heat, and stress — it can drift 5-15 bpm in either direction. HR zones lag effort by 30-90 seconds, so they're poor for short intervals. Max HR drops with age but not at the textbook "220 minus age" rate — that formula is wrong for most trained athletes. Where possible, use power as the primary control and HR as the cross-check.

When to see a coach

If your HR is 10+ bpm above normal at the same power for several days running, you're likely under-recovered, ill, or over-reaching. That's where coaching and structured monitoring beats more numbers — it changes how you respond.

FREQUENTLY ASKED QUESTIONS

How do I find my Max HR?+

The most accurate way is a true all-out test — a hard 5-minute effort at the end of a race or hard interval session, with a 30-second sprint to finish. Take the highest reading. Avoid the "220 minus age" formula — it's a population average and is wrong for most trained athletes by 5-15 bpm in either direction.

What is LTHR in cycling?+

LTHR is your Lactate Threshold Heart Rate — the heart rate corresponding to your FTP. The simplest way to estimate it is to do a 20-minute FTP test and record the average heart rate for the last 20 minutes. LTHR is more useful than Max HR for setting zones in trained athletes, because it scales better with training adaptation.

Should I train with heart rate or power?+

Power is the primary control if you have access to it — instant, doesn't drift, isn't affected by heat or stress. Heart rate is a useful cross-check and is fine as a primary signal for endurance riders without a power meter. The best setup is power as the target, HR as the sanity check.

Why is my heart rate higher in summer?+

Cardiac drift in heat is real — your heart works harder to pump blood to skin for cooling, which raises HR for the same power output by 5-15 bpm. Don't chase HR zones when it's hot; let power lead and accept HR runs higher than usual.