Enter a recent race or honest time trial, then use the result to set your Easy, Marathon, Threshold, Interval, and Repetition paces. The most useful output is not just the fastest pace on the table: it is knowing which pace belongs to recovery volume, controlled threshold work, and faster interval sessions.
Start by applying the Easy range to most weekly mileage, use Threshold pace for tempo or cruise-interval workouts, and treat Interval/Repetition paces as precise tools for short quality sessions. Recalculate after a fresh race, a clear fitness change, or every 4-8 weeks in a structured block.
Training zones divide effort into practical ranges for different workout goals. This calculator estimates pace-based zones from a recent race result. Heart-rate zones are included here as context, but use the heart rate calculator if you want HR-based zones from age, resting heart rate, and max-HR assumptions.
| Zone | % Max HR | Feel | Purpose |
|---|---|---|---|
| Zone 1 - Recovery | 50-60% | Very easy, fully conversational | Active recovery, warm-up/cooldown |
| Zone 2 - Aerobic Base | 60-70% | Easy, comfortable conversation | Aerobic base building |
| Zone 3 - Aerobic Endurance | 70-80% | Moderate, can speak in sentences | Steady endurance, marathon context |
| Zone 4 - Threshold | 80-90% | Comfortably hard, short phrases only | Threshold and tempo work |
| Zone 5 - VO2 Max | 90-100% | Hard, can barely speak | Short high-intensity repetitions |
A common recreational-running mistake is letting easy days drift into moderate effort too often. Many endurance programs keep most training volume easy and use a smaller amount of hard work, but the best distribution depends on your background, recovery, and race goal.
Heart-rate-zone calculations depend on maximum heart rate (MHR), which is hard to estimate perfectly. The classic age-based formula (220 - age) is a population average and can be materially off for individuals. Better inputs include:
Resting heart rate matters too. A well-trained runner might have a lower resting HR than a beginner with the same MHR, so HRR-based zones can differ meaningfully between athletes.
The Karvonen formula calculates target heart rate as a percentage of Heart Rate Reserve (HRR), which incorporates resting heart rate. Formula: Target HR = ((MHR - Resting HR) x Intensity%) + Resting HR.
Example: Runner with MHR = 185, Resting HR = 50, HRR = 135:
| Zone | % HRR | Target HR (this runner) |
|---|---|---|
| Zone 1 | 50-60% | 118-131 bpm |
| Zone 2 | 60-70% | 131-145 bpm |
| Zone 3 | 70-80% | 145-158 bpm |
| Zone 4 | 80-90% | 158-172 bpm |
| Zone 5 | 90-100% | 172-185 bpm |
Compare to the same runner using straight % MHR: Zone 2 would be 111-130 bpm. Neither method is perfect, but HRR can be more useful when resting heart rate differs substantially between runners.
Some runners find it more practical to train by pace rather than heart rate. Heart rate can be affected by fatigue, heat, caffeine, and dehydration, while pace-based zones are anchored to your current race performance.
Approximate pace zones for a runner with a 5K time of 25:00 (VDOT ~45):
| Zone | Purpose | Pace /km |
|---|---|---|
| Zone 1 - Recovery | Active recovery | 7:15-8:00+ |
| Zone 2 - Easy | Aerobic base | 6:30-7:15 |
| Zone 3 - Marathon | Marathon-race pace | 5:45-6:15 |
| Zone 4 - Threshold | Tempo runs | 5:10-5:25 |
| Zone 5 - Interval | VO2 max intervals | 4:40-4:55 |
These paces should be updated every 4-8 weeks as fitness changes. Running easy days too fast can turn recovery runs into moderate workouts that accumulate fatigue without serving the intended purpose.
Many endurance programs use an easy-heavy distribution: most training at low intensity, with a smaller amount of threshold or high-intensity work. This is often described as polarized or "80/20" training, although real-world plans vary by athlete and event.
The practical lesson for most runners is simple: keep easy days easy enough that they support recovery and volume, then make quality sessions purposeful. Spending too much time at a moderately hard effort can make it harder to recover for the sessions that matter.
For a runner training 5 hours per week, a simple easy-heavy week might look like:
Use the calculated paces as starting points and adjust for experience, fatigue, weather, terrain, and injury history.
Here's one way to structure a week of training using zones for a recreational runner targeting a 10K or half marathon:
The total distribution here is easy-heavy, with only a small number of harder sessions. Adjust based on your fitness level: beginners should usually keep most sessions easy until their aerobic base and durability improve.
The simplest method: Zone 1 = 50–60% MHR, Zone 2 = 60–70%, Zone 3 = 70–80%, Zone 4 = 80–90%, Zone 5 = 90–100%. For more accuracy, use the Karvonen formula with your resting HR: Target HR = ((MHR − Resting HR) × Intensity%) + Resting HR. Example: MHR = 180, Resting HR = 55. Zone 2 target (70%): ((180−55) × 0.70) + 55 = 87.5 + 55 = 142.5 bpm. The Karvonen method accounts for your fitness level and gives more personalized zones than the simple % MHR approach.
Zone 2 (easy aerobic) is the foundation of all marathon training. The majority (70–80%) of your weekly mileage should be in Zone 2. Zone 4 (threshold) is the second priority, building lactate threshold for sustained pace. Zone 5 intervals are valuable but secondary to high-volume aerobic work for marathon runners.
Running many miles at an easy effort builds the aerobic base that supports faster racing. Easy running lets you accumulate volume with less recovery cost than hard training. Running too many miles too fast can create fatigue that compromises quality sessions.
Zone 2 should feel comfortable and fully conversational — you can speak in complete sentences without breathing being interrupted. If you can't hold a basic conversation or feel like you're working, you're likely in Zone 3+. Many runners are shocked to see how slow their 'easy' run needs to be. Initially, your Zone 2 HR might mean running at what feels like a jog. That's correct.
Using the age-based formula (220 − age): MHR ≈ 185. Zone 2 = 60–70% = 111–130 bpm. With Karvonen (assuming resting HR 60): Zone 2 = 60–70% HRR = 125–140 bpm — meaningfully higher. The Karvonen method is more appropriate for fit individuals. Also note that age-based MHR has ±10–15 bpm individual variation, so your actual Zone 2 could be 5–15 bpm higher or lower.
Both have merits. Heart rate training is more physiologically precise — it accounts for fatigue, heat, and terrain — but can vary daily due to external factors. Pace training is consistent and measurable but doesn't account for conditions. Many coaches recommend using HR for easy runs (to prevent going too hard) and pace for quality workouts (to hit specific training stimuli). GPS watches make combining both approaches easy.
Many recreational runners do well with 1-2 quality sessions per week, depending on training age, total volume, recovery, and race goal. Adding more hard sessions increases recovery demands and should be done cautiously. Quality over quantity applies to hard training sessions.
Daniels uses 5 pace-based zones (Easy, Marathon, Threshold, Interval, Repetition) derived from VDOT race equivalency tables. Pfitzinger uses 4 primary zones (Recovery, General Aerobic, Lactate Threshold, VO2max) with heart rate as the primary metric. Hansons simplify to 3 categories (Easy, Speed/SOS, Strength/SOS) and emphasize cumulative fatigue over precise zone hitting. All three systems work — the best one is the one you'll follow consistently.
Pfitzinger's GA run is a steady effort between recovery pace and marathon pace (70–81% max HR). It's faster and more purposeful than a typical easy run but not hard enough to require extended recovery. GA runs form the bulk of weekly mileage in Pfitzinger's plans and are where most aerobic development happens for serious runners. Think of it as your "bread-and-butter" training pace — not so easy it feels like jogging, not so hard it compromises your next quality session.
In the Hansons method, you run 6 days per week, which means you start most quality sessions on pre-fatigued legs. This means your perceived effort at any given pace is higher than in a traditional program where you rest before hard sessions. The practical effect: your threshold pace may feel like VO2 max effort, and your easy pace may feel moderately challenging. Hansons coaches say this is intentional — training under fatigue simulates race conditions more accurately than fresh-legged workouts.
Jack Daniels, PhD, developed arguably the most influential pace-based training zone system in distance running. Rather than using heart rate percentages (which vary by individual and are affected by daily conditions), Daniels defines five training intensities based on race performance — each targeting specific physiological adaptations.
Daniels' five training intensities explained in depth:
| Zone | Name | % VO2max | Effort | Primary Adaptation | Typical Duration |
|---|---|---|---|---|---|
| E | Easy | 59–74% | Conversational | Aerobic base, capillary development, mitochondrial density | 30–150 min |
| M | Marathon | 75–84% | Comfortably steady | Glycogen management, fat utilization, marathon-specific endurance | 40–110 min |
| T | Threshold | 83–88% | Comfortably hard | Lactate clearance, lactate threshold improvement | 20–60 min |
| I | Interval | 95–100% | Hard, controlled | VO2max development, aerobic power | 3–5 min reps |
| R | Repetition | 105–120% | Fast, powerful | Running economy, speed, neuromuscular coordination | 200–400m reps |
A useful Daniels-style principle is that each training zone has a specific purpose, and running faster is not always better. Easy pace that is too fast can add fatigue, while threshold work that is too aggressive may turn into a different stimulus than intended.
His prescription methodology:
Daniels' system is the foundation of this calculator. When you enter a race time, the calculator computes your VDOT and derives all five training paces — giving you a complete, personalized training prescription from a single data point.
Pete Pfitzinger's zone system, detailed in Faster Road Racing and Advanced Marathoning, uses a similar structure to Daniels but with subtle differences in how zones are applied within training plans. Pfitzinger defines four primary training intensities:
Pfitzinger's distinguishing contribution is the General Aerobic (GA) run — a zone between easy and marathon pace that most other systems don't explicitly prescribe. GA runs are faster than Daniels' Easy pace but slower than Marathon pace. For Pfitzinger, this is where the bulk of aerobic development happens for serious runners, because the pace is fast enough to produce meaningful aerobic stress without the recovery cost of threshold work.
His medium-long runs (MLRs) — typically 11–15 miles at GA effort — are a hallmark of his marathon and half marathon programs. These provide a second weekly dose of extended aerobic work that supplements the traditional weekend long run.
The Hansons method uses a streamlined zone system they call SOS (Something of Substance) — quality workouts that provide specific training stimuli. Their zone philosophy is pragmatic: rather than prescribing 5 distinct physiological zones, they organize training into three categories with clear purposes.
Hansons' training zone structure:
| Category | Hansons Name | Pace Reference | Purpose | Weekly Frequency |
|---|---|---|---|---|
| Easy | Easy runs | MP + 1:00–2:30/km | Recovery, aerobic base, volume accumulation | 3–4 days |
| SOS: Speed | Speed work | 5K–10K race pace | VO2max, running economy, neuromuscular speed | 1 day (Tuesday) |
| SOS: Strength | Tempo runs | HM pace to MP − 10 sec/km | Lactate threshold, race-specific endurance | 1 day (Thursday) |
| Long | Long runs | MP to MP + 0:45/km | Endurance, glycogen management, mental toughness | 1 day (Sunday) |
The Hansons philosophy on training zones is fundamentally different from Daniels and Pfitzinger in one key respect: it gives more weight to cumulative fatigue. Rather than treating exact pace targets as the only signal, Hansons-style training considers how quality work feels when it is done on legs that are not fully fresh.
This means a Tuesday speed session at 5K pace may feel harder when it follows previous training load. That does not make the calculator wrong; it means the pace target should be interpreted inside the week as a whole.
For training zone calculator users, the Hansons approach suggests: use the calculated zones as starting points, but adjust based on how you feel that day. If cumulative fatigue makes your threshold pace feel too hard, slow down slightly rather than forcing a number.
Training zones are most useful when they help you choose the right effort for the workout purpose: easy enough for aerobic volume, controlled enough for threshold work, and hard enough only when the session calls for it.
VDOT-style paces should be treated as starting points from a recent race, then adjusted for terrain, heat, fatigue, and whether the input race truly represented current fitness.
General aerobic running sits between recovery jogging and harder race-specific work. It can be useful, but it should not crowd out recovery or the key sessions in the plan.