Heart Rate Calculator

How to Use Heart Rate Calculator

1. Step 1: Choose Method

   Select age‑based estimate or enter a known max heart rate.

2. Step 2: Enter Age & Resting HR

   Type your age and resting heart rate (for Karvonen HRR results).

3. Step 3: Pick Formula

   Choose 220−age or Tanaka (208 − 0.7×age) for max HR if estimating.

4. Step 4: Select Intensity

   Use the slider or quick‑pick chips to set workout intensity.

5. Step 5: Review Zones

   Compare Zones 1–5 targets using %MHR and Karvonen methods.

6. Step 6: Train Smart

   Use targets for warm‑ups, Zone 2 endurance, tempo, and intervals.

Key Features

• Age or known Max HR
• %MHR and Karvonen options
• Zones 1–5 table
• Quick intensity slider
• Mobile‑first inputs

Understanding Results

Formulas used

Max heart rate (Max HR) can be estimated from age using common population formulas such as 220 − age or the Tanaka model (208 − 0.7×age). If you already know your Max HR from a recent test or hard race, use that value instead of an estimate.

Target heart rate can be calculated two ways: by a percent of Max HR (%MHR) or by the Karvonen method, which uses heart rate reserve (HRR). HRR is Max HR − Resting HR. The Karvonen target is Resting HR + (% × HRR). Both approaches are shown here.

Ranges and interpretation

Many plans divide training into five zones. As a starting point, Zone 1 ≈ 50–60%, Zone 2 ≈ 60–70%, Zone 3 ≈ 70–80%, Zone 4 ≈ 80–90%, and Zone 5 ≈ 90–100% of Max HR or HRR. Zone 1 and 2 support easy endurance and recovery. Zone 3 feels steady. Zone 4 targets threshold and tempo. Zone 5 is very hard work for short intervals.

If you are building an endurance base, focus most time in Zone 2. For races, combine easy volume with bouts of Zone 3–4. Intervals that briefly reach Zone 5 can improve top‑end power. Adapt your targets with your fitness, sleep, and stress.

Assumptions & limitations

Age‑based formulas are helpful but not perfect. Day‑to‑day heart rate is affected by heat, dehydration, caffeine, medications, and device placement. Wrist sensors can lag or under‑read during intervals; a chest strap is usually more accurate. Always listen to your body and adjust as needed. This tool is for education only and does not provide medical advice.

Complete Guide: Heart Rate Calculator

Use our heart rate calculator to estimate max HR, heart rate reserve, and smart training zones with %MHR or Karvonen. Enter age or known max for fast targets.

The goal is simple: give you clear target numbers you can actually use in today’s workout. Your inputs stay on your device, and you can tailor results to match your fitness, equipment, and training style.

How this heart rate calculator works

The calculator estimates your maximum heart rate from age using either 220−age or the Tanaka formula (208 − 0.7×age). If you already know your Max HR from a recent test or race, you can enter it directly for more precise results. With Max HR in hand, targets are created in two ways: by percent of Max HR (%MHR) and by Karvonen (Heart Rate Reserve) which also uses your resting heart rate.

Both methods are valid. %MHR is simpler and common in group classes. Karvonen adjusts for your personal resting heart rate, which can be lower in trained athletes and higher when you are stressed or fatigued. Seeing both side‑by‑side makes it easy to choose the version that fits how you train.

Why give two answers? Because physiology is personal. Two people of the same age can have different resting heart rates, stroke volumes, and recovery patterns. Showing both %MHR and HRR lets you triangulate on a range that feels sustainable for the session you planned. If both methods give similar numbers, that’s a good sign your inputs are reasonable.

On busy days, keep things simple: pick your quick intensity (for example, Zone 2 or Tempo), glance at the bpm target, and get moving. The layout is built mobile‑first so you can adjust on the fly without hunting for tiny controls. When you want more depth, open the zones table and compare %MHR versus HRR ranges.

Picking your Max HR

Age‑based equations are population averages, not personal limits. You might be higher or lower by 10–15 beats and still be perfectly normal. That’s why perceived effort and pace still matter. If you have a reliable chest‑strap record from an all‑out effort, entering your known Max HR will usually tighten the targets for you.

For a quick and safe estimate, start with Tanaka (208 − 0.7×age). It tends to be slightly lower and often closer to the truth than 220−age. As your training progresses, you can refine the value using hard workouts, a race finish, or a supervised threshold test.

Practical testing tips: warm up for at least 10–15 minutes, include several strides or pickups, and choose a gradual hill. Start strong but controlled, then finish the final minute all‑out. Use a chest strap if possible and stop if you feel unwell. The highest value you see in the last minute is a reasonable working Max HR for training purposes.

You do not need to test often. Most athletes can set Max HR once, then revisit at the start of a new season or after major changes in fitness. Daily variation in fatigue will shift targets more than small changes in Max HR, so focus your energy on consistent training and recovery.

A note on age differences: as we get older, Max HR trends downward, but not always at the same rate for everyone. Some masters athletes maintain higher max values than equations predict. That’s another reason to validate with real training data when you can.

Should you use HRR (Karvonen) or %Max HR?

Both methods try to keep your effort inside a target range, but they scale differently. Karvonen adds resting heart rate and often lines up better with how the workout feels. If your resting HR is quite low, %MHR zones may feel too hard. If your resting HR is elevated, %MHR zones can feel too easy. That’s where HRR shines.

In practice, choose one method and stick with it for a training block. Consistency allows your body to adapt and helps you compare sessions fairly. The calculator shows both so you can learn how they differ before you commit.

If you are new to structured training, pick HRR for day‑to‑day guidance and cross‑check with %MHR. As you gain experience, you may switch to %MHR for simplicity if it matches how you feel. For athletes with very low resting HRs, HRR is often a better guide for easy days because it prevents creeping too high.

What if your resting HR is inconsistent? Measure it at the same time each morning after waking, or sit quietly for 5 minutes before recording. A short weekly average smooths out noise and makes your Karvonen targets more useful.

What heart rate zones really mean

Zone 1 and Zone 2 are the backbone of aerobic fitness. They build endurance, support recovery, and help you handle more total training later. Zone 3 sits in the middle—steady, sustainable, and useful for longer continuous efforts. Zone 4 moves up to your lactate threshold region, where pace feels honest but controlled. Zone 5 is hard, short, and powerful, best used in carefully planned intervals with full recovery.

There is no single universal zone system. Some coaches compress or expand boundaries; others add a sixth zone. The ranges used here (50–60, 60–70, 70–80, 80–90, 90–100%) match common five‑zone models and are flexible enough for most training plans. If you prefer a different system, use the intensity slider to set your custom targets.

Weekly distribution examples: beginners often thrive on mostly Zone 1–2 with a small dose of Zone 3, such as one steady session. Intermediate endurance athletes might follow an 80/20 style where about 80% of time is easy and 20% is moderate‑to‑hard spread across tempo and interval work. Masters athletes sometimes need more recovery between hard sessions but handle higher overall Zone 2 volume well.

How to set your Zone 2 in seconds

Tap the Zone 2 quick pick in the calculator. You’ll see both %MHR and Karvonen numbers. If they disagree by more than a few beats, try the Karvonen range first—it reflects your resting HR and often feels more natural for easy endurance. On any given day, you can nudge the intensity up or down a few beats to keep the effort comfortable and nose‑breathing easy.

If you run or ride, combine the targets with your usual pace metrics. For extra context while building your base, try our Zone 2 heart rate calculator and compare results with the running pace calculator. Both tools help you stay honest on easy days.

Two simple field checks: you should be able to hold a full conversation without gasping, and your breathing should stay rhythmical without frequent mouth‑only breathing. If either fails, lower the intensity a few beats and re‑check in 2–3 minutes.

Cyclists and rowers often see slightly lower Zone 2 bpm than runners of similar fitness because different muscles are engaged and loading is different. That’s normal. Keep your zone definition activity‑specific and compare like with like.

Using heart rate for intervals and tempo

Heart rate rises with a delay, especially in the first minute of a hard rep. That means instant pace or power is a better guide for the early seconds of an interval. Heart rate becomes more informative mid‑rep and across sets. For tempo work near threshold (upper Zone 3 to Zone 4), HR is an excellent anchor: you should reach your target, hold steady, and recover predictably.

If your training is cycling‑focused, pair heart rate with a power target. If you prefer running, pair heart rate with pace. To explore the relationship, check the VO2 max calculator and the race pace calculator. Over time you’ll learn how a given heart rate maps to the speeds you can sustain.

Sample structures you can adapt: (1) Threshold repeats — 3×8 minutes in upper Zone 3/low Zone 4 with 3–4 minutes easy between. (2) VO₂ short intervals — 8–12×1 minute hard in Zone 5 with full rest. (3) Tempo run — 20 minutes continuous in Zone 4 after a long warm‑up. Let heart rate settle for 2–3 minutes before judging whether you are inside the day’s target range.

Heat and altitude change the picture. In summer conditions, heart rate drifts upward for the same pace (cardiac drift). For these days, cap your session at the top of the intended zone even if pace slows. At altitude, expect higher heart rates and slower paces until you acclimate.

Accuracy: wrist vs chest straps and practical tips

Optical wrist sensors are convenient but can lag or under‑read during motion, cold weather, or high‑intensity reps. A chest strap generally gives cleaner data during intervals and sprints. Wet the electrodes, tighten the band, and allow a short warm‑up so your readings settle before you judge the session.

Hydration, heat, caffeine, stress, sleep, and some medicines shift your numbers. That’s normal. Adjust your plan by feel. If your heart rate refuses to rise under effort, you may be fatigued or under‑recovered. If it spikes unusually high for easy work, back off and reassess.

For general education about heart‑rate training zones, see the American Heart Association’s overview (heart.org). It explains the idea of target zones and why easy‑to‑moderate work is the foundation for long‑term cardiovascular health.

Indoor vs outdoor differences are normal. Treadmill running, for example, can show slightly lower heart rates at the same pace because airflow and belt mechanics reduce impact cost. On a hot, sunny day outdoors, expect the opposite. Use the numbers as a guide and re‑center on effort when conditions change.

Swim heart rate can be trickier to capture. Optical sensors struggle underwater, and chest straps work only with compatible devices. If HR data is unreliable in the pool, pace and rest intervals become the primary guides, with HR as a secondary reference when you can measure it.

Common mistakes and how to fix them

The most frequent mistake is forcing every day to be hard. That creeps you into middle zones and leaves you too tired to do the real quality work. Keep easy days truly easy and save your mental matches for focused sessions. Another trap is chasing a single perfect formula. Estimates are fine—learn how your body responds and refine with experience.

A second mistake is mixing methods mid‑block. If you start a plan using Karvonen, don’t switch to %MHR every other week. Small differences between systems can compound confusion. Choose one approach, stick with it for several weeks, then evaluate your progress and adjust.

Finally, avoid reading too much into outlier days. Heat waves, allergies, lack of sleep, and travel can distort your numbers. Use your targets as guardrails, not handcuffs.

Two more to watch for: relying on wrist‑only data for very short intervals, and skipping warm‑ups. Short reps may show low HR early even when the effort is high; use time, pace, or power for those first seconds. A good warm‑up not only prevents injury, it brings HR response closer to steady‑state so targets make sense sooner.

When to seek medical or coaching advice

If you notice chest pain, dizziness, unexplained shortness of breath, or palpitations during exercise, stop and consult a clinician. If you are returning to training after illness, injury, or with a new diagnosis, a gradual plan from a qualified professional can keep you safe while you regain fitness.

Coaches can also help you set the right mix of Zone 1–2 volume and Zone 3–5 stress for your goals. They may use lactate testing or field protocols to replace age‑based estimates with personal thresholds. To explore higher‑level planning on your own, start with our heart rate zone calculator and the max heart rate calculator.

If you are on medications that affect heart rate (for example, beta‑blockers), ask your clinician how to individualize training targets. In some cases, perceived effort, breathing cues, and talk‑test become more useful than standard percentages.

For general population guidance on physical activity intensity, the CDC provides plain‑language resources and target ranges (cdc.gov). These are helpful if you are just getting started and want a conservative plan.

Next steps and helpful tools

Build your aerobic base with frequent Zone 2 sessions. Layer in one threshold or tempo workout most weeks and short VO₂ reps when you are fresh. Track sleep, hydration, and weekly volume. If you cross‑train, keep heart rate targets consistent across activities.

For structured pacing, the running pace calculator converts your target intensity into real‑world splits. To understand your engine, try the VO2 max calculator. To see how hard your sessions burn energy, check the calories burned calculator. When you’re ready for long‑term planning, use training zones from the heart rate zone calculator and refine your easy days with the Zone 2 heart rate calculator.

Remember: numbers are tools, not rules. Use this heart rate calculator to guide your effort, then listen to your body. With consistency and smart recovery, your heart rate at any given pace will drop over time—that’s fitness improving.

If you prefer to work from the top down, start with the max heart rate calculator, then bring those values back here to generate zones and a day‑to‑day target number using your resting HR. Either path leads to the same destination: practical training guidance that fits you.

Frequently Asked Questions