favorite

Target Heart Rate Calculator | Estimate zones with Karvonen

Quick reference

Heart rate zones (% of max HR):

Zone	% of HRmax	Purpose
Warm-up	50–60%	Recovery, easy effort
Fat burn	60–70%	Endurance base
Cardio / aerobic	70–80%	Fitness building
Threshold	80–90%	Performance
Peak	90–100%	Short intervals

monitor_weight A starting point, not a diagnosis

This calculator gives you the same number a clinician would compute by hand from your inputs. It is informational, never a substitute for a doctor. If a result surprises you, write it down and discuss it at your next appointment — that conversation is the goal, not a verdict from a webpage.

science Built from peer-reviewed formulas

Every health calculator on CalcaTools uses an equation from the WHO, NIH, ACOG, CDC, or a published peer-reviewed paper. The exact citation is in the "Formula & methodology" section. We re-check sources quarterly and update the page when guidance changes — the "Last reviewed" date is at the top.

volunteer_activism Designed for real people

Health calculations only help if you can actually use them. We use plain-English labels (no jargon), accept both metric and US units, and show what a "normal" range looks like alongside your result — so you understand what the number means, not just what it is.

lock Private by design

Your weight, height, age, pregnancy details, and any other health input never leave your browser. Calculations run client-side; nothing is logged or stored on our side. We don't want your medical data — we just want the formula to work for you.

Interpretation guide

Two estimation methods:

Method	Formula
Max HR	220 - age
Plain % method	HRmax x zone %
Karvonen (HRR)	((HRmax - rest) x %) + rest

lightbulb Worked example

Let's say you are using the Target Heart Rate Calculator. Enter your age and resting heart rate, and this calculator estimates your maximum heart rate and returns your target heart rate zones — warm-up, fat-burn, cardio, and peak — using the Karvonen Enter the values that match your situation into the input fields and press calculate — using realistic numbers makes the result directly useful for you.

Result: The calculator instantly applies the formula HRmax = 220 - age; Karvonen: target = ((HRmax - resting HR) x intensity%) + resting HR and returns the result with appropriate precision.

What this means: Read the result in the context of what you are measuring. The step-by-step breakdown lets you confirm the math and understand which input most affects the outcome.

Formula & methodology

Formula: HRmax = 220 - age; Karvonen: target = ((HRmax - resting HR) x intensity%) + resting HR

The Target Heart Rate Calculator is built on a well-established calculation method. It uses the formula HRmax = 220 - age; Karvonen: target = ((HRmax - resting HR) x intensity%) + resting HR to turn your inputs into a reliable result. Enter your age and resting heart rate, and this calculator estimates your maximum heart rate and returns your target heart rate zones — warm-up, fat-burn, cardio, and peak — using the Karvonen method. It gives you the The steps are shown on the page so you can follow the reasoning from input to output.

The calculator estimates maximum heart rate as 220 minus age, then sets training zones as percentages of it. The simple method multiplies HRmax by the zone percentage; the more personalized Karvonen method uses heart rate reserve (HRmax minus resting HR) for tighter zones. Training in the right zone targets specific adaptations — easy aerobic base, cardio fitness, or high-intensity performance. Resting heart rate makes the Karvonen result more individual.

What is the Target Heart Rate Calculator?

The Target Heart Rate Calculator is a free, browser-based health calculator tool that helps you Enter your age and resting heart rate, and this calculator estimates your maximum heart rate and returns your target heart rate zones — warm-up, fat-burn, cardi. Instead of working through the math by hand or in a spreadsheet, you enter your values and the calculator returns an accurate result instantly — while still showing the formula and the steps so you can verify the reasoning. It is designed for quick everyday use: no sign-up, no installation, and everything runs locally in your browser for complete privacy.

How to use the Target Heart Rate Calculator

Enter the required values into the input fields.
Press the calculate button — the result appears immediately, updated live as you change any value.
Read the step-by-step breakdown below the result to see exactly how the calculation was performed.
Use the interpretation guide to understand what the result means for your situation, and try different inputs to see how they change the outcome.

How to use the Target Heart Rate Calculator

Enter your age and your resting heart rate — measured first thing in the morning, before getting up — then choose the intensity zone you are training in, from light warm-up (50–60%) to hard interval work (80–90%). The tool applies the Karvonen formula: Target = ((HRmax − resting HR) × intensity%) + resting HR, where HRmax = 220 − age. The result is the beats-per-minute range that matches your chosen effort level.

Interpreting your result

The Karvonen method is more accurate than the simple percentage-of-max approach because it accounts for your personal fitness baseline — a fit person with a low resting rate trains in a different range than someone with a higher resting rate, even at the same age. The zones map to real training effects: 50–60% builds base endurance and recovery, 70–80% improves aerobic capacity and is the fat-burning-plus-fitness sweet spot, and 80–90% develops speed and power. Check your pulse at the wrist or neck for 15 seconds and multiply by 4 to see whether you are in range.

Common mistakes to avoid

The most common error is using the generic 220 − age formula when your resting heart rate is known — the Karvonen adjustment usually shifts the target meaningfully. Second, measuring resting heart rate after coffee, stress, or exercise, which inflates it and raises every target. Third, treating the zone as a strict pass/fail: staying a few beats above or below is fine, and beginners should stay at the low end of the zone. Finally, ignoring medications — beta-blockers and other drugs change heart-rate response, so check with your doctor before training to a formula.

Tips for best results

Take your resting heart rate for three consecutive mornings and average the readings. Use the 70–80% zone for most cardio sessions, and only add 80–90% intervals once you have a consistent base. A wearable with a chest strap is more accurate than wrist optical sensors for hard intervals. Remember that the formula is a population estimate — if you train by feel and your breath is conversational at the low end and gasping at the top, you are in the right ballpark. Recalculate after several months of training as your resting rate drops.

Authoritative source: U.S. Centers for Disease Control and Prevention

Frequently asked questions

How do I calculate my maximum heart rate?

Enter the required values into the input fields and press the calculate button. The tool applies the formula HRmax = 220 - age; Karvonen: target = ((HRmax - resting HR) x intensity%) + resting HR and returns the result with a short explanation of each step, so you can check the working yourself.

What is my target heart rate for fat burning?

The Target Heart Rate Calculator is free, private, and accurate: it runs entirely in your browser (no uploads, no accounts), applies the standard calculation, and explains each step so you can verify the result. Enter your age and resting heart rate, and this calculator estimates your maximum heart rate and returns your target heart rate zones — warm-up, fat-burn, cardio, and peak — using the Karvonen method. It gives you the beats-per-minute range for each zone so There is no limit on usage, and it works on any device.

What is the Karvonen formula?

The Target Heart Rate Calculator uses the standard HRmax = 220 - age; Karvonen: target = ((HRmax - resting HR) x intensity%) + resting HR. You enter your values, and the calculator applies the formula step by step, showing the working so you can verify the math and understand how the result is derived rather than trusting a black box.

Why include resting heart rate?

Resting heart rate reflects your aerobic fitness baseline — a fit person's heart pumps more per beat, so it beats fewer times per minute. The Karvonen formula includes it because the same intensity % produces a different target heart rate for a fit person than an unfit one. Target = ((HRmax − resting) × intensity%) + resting reserves the training range above your baseline instead of above zero.

Is 220 minus age accurate?

The Target Heart Rate Calculator applies the standard formula: HRmax = 220 - age; Karvonen: target = ((HRmax - resting HR) x intensity%) + resting HR. It is tested against published worked examples before launch and uses native double-precision arithmetic, so results are accurate to typical precision for the values you enter — with no intermediate rounding that could distort the answer.

How accurate is 220 minus age for max heart rate?

Roughly — it's a population average with a standard deviation around ±10 bpm, so a true max can easily sit 10–20 beats off. Better formulas exist (208 − 0.7 × age is one), but every estimate is a guess until measured. For training zones, a field test or lab measurement beats any formula.

What does the Karvonen formula add over simple percentages?

It anchors zones to heart rate reserve — (HRmax − resting HR) × intensity% + resting HR — so two 40-year-olds with different resting rates get different targets. Plain “% of max” ignores fitness level; Karvonen accounts for it. A fitter person with a lower resting HR gets appropriately higher zone boundaries.

Which zone should I train in for fat burning?

The 60–70% of HRR zone is labeled “fat burn” because a higher share of calories comes from fat at low intensity — but total calories burned are lower than in harder zones. For fat loss, total energy expenditure matters more than the fuel mix. Use the zone for easy base building, not as a weight-loss shortcut.

Should I measure resting heart rate or just guess?

Measure it — first thing in the morning, before coffee, averaged over several days. A guessed 70 versus an actual 55 shifts every Karvonen zone by about 10 bpm. The whole method pivots on the reserve between resting and max, so a wrong resting value corrupts all the zones.

Explore the full health & fitness toolkit

Every CalcaTools health calculator — BMI, calories, macros, heart rate, pregnancy, and body composition — with practical guidance on every result.