Normal ECG values chart: Adult and pediatric reference ranges

A normal ECG values chart lists the expected range for every measurement on an electrocardiogram, so you can spot an abnormal tracing at a glance. A resting adult’s normal heart rate is 60–100 bpm, with a PR interval of 120–200 ms and an axis between −30° and +90°. QRS duration stays under 110 ms in men and 100 ms in women, and QTc tops out around 450 ms and 470 ms respectively.

Children run on different numbers. Their heart rates are higher, their PR and QRS limits are lower, and their QT values shift with age and rate. Our free PDF covers both groups, and this guide walks through the reading order clinicians use to apply it.

Key takeaways

In adults, a normal ECG shows a heart rate of 60–100 bpm and a PR interval of 0.12–0.20 s. QRS duration stays under 110 ms in men and 100 ms in women.

Every value assumes the standard 25 mm/s paper speed and 10 mm/mV calibration. At those settings, one small box is 0.04 s and one large box is 0.2 s.

Pediatric ECG values differ substantially from adult ranges, with higher heart rates and shorter PR intervals. Pediatric QT/QTc is age- and rate-dependent rather than simply shorter, so compare every child against an age-stratified chart.

Practice software such as Pabau lets you record ECG findings in custom forms and notes, keeping them in the patient record for compliance audits.

What is a normal ECG values chart?

It is a clinical reference table that defines the expected range for every measurable parameter on a 12-lead electrocardiogram. A measurement outside its range signals a possible abnormality that needs clinical correlation and, often, further investigation.

The ranges draw on guidance from the American Heart Association (AHA), the American College of Cardiology (ACC), and the European Society of Cardiology (ESC). These bodies publish slightly different limits, based on different populations and correction formulas. Whichever chart you use should name its source standard.

Normal adult values by parameter

A complete chart covers 10 parameters. These are the adult resting values this guide and the PDF use.

How to read an ECG against the chart

The chart works best inside a fixed reading order: rate, rhythm, axis, intervals, then morphology. Following the same sequence every time means no parameter gets skipped.

1. Verify paper speed and calibration. Confirm the ECG was recorded at the standard 25 mm/s and 10 mm/mV, which are marked on the strip. If either differs, every interval you measure is wrong until you recalculate it.
2. Measure heart rate. Count the QRS complexes in a 6-second strip (30 large boxes) and multiply by 10. Compare the result with 60–100 bpm for an adult at rest. Below 60 bpm is bradycardia and above 100 bpm is tachycardia.
3. Assess rhythm. Identify the rhythm, whether normal sinus rhythm, atrial fibrillation, flutter or premature beats. Normal sinus rhythm needs regular P-P and R-R intervals, one P wave before each QRS, and a normal PR interval. Irregular intervals or missing P waves need further investigation.
4. Calculate cardiac axis. Use leads I and aVF. A normal axis runs from −30° to +90°. Left, right or extreme deviation points to a conduction abnormality or chamber enlargement. Many machines calculate the axis automatically, so check it by hand if the result looks off.
5. Measure intervals and compare them to the chart. Using 0.04 s per small box, measure the PR interval, QRS duration and QT interval. Check each against the chart and note whether it falls within range. For QT, use the corrected value (Bazett or Fridericia, depending on your standard).

After the intervals, compare P and T wave shape with the chart’s lead-specific norms, and check for ST elevation or depression. When ST changes appear alongside chest pain, a troponin levels chart helps you judge whether the biomarkers support myocardial injury. Correlate any abnormal value with the patient’s history, symptoms and prior ECGs before deciding it matters.

Who uses the chart

Any clinician who orders, reads or documents ECGs gets value from a shared set of reference ranges. The main users are:

• Cardiologists and cardiac nurses, for routine ECG interpretation and patient education
• Emergency and urgent care clinicians, for rapid assessment of chest pain, arrhythmia and syncope
• Primary care and internal medicine physicians, for screening ECGs, pre-operative clearance and risk stratification
• Sports medicine physicians and physical therapists, for baseline ECGs before stress testing or return-to-sport clearance
• Occupational health clinicians, for periodic screening in high-risk jobs such as pilots and commercial drivers
• Nursing students and clinicians in training, for learning interpretation against a fixed standard

In primary care, the chart earns its place at annual physicals and pre-operative visits, where one physician may read several ECGs a day. If your practice is comparing primary care software, check that ECG findings can be recorded in the same patient file as the visit.

ECG intervals by age: Pediatric vs adult ranges

Applying adult values to a child is one of the most common errors in ECG interpretation. Children have higher resting heart rates, faster conduction and different chamber proportions. Read a child’s ECG against an adult chart and normal findings start to look abnormal.

Key age-related differences

Heart rate. Newborns (0–3 months) run at 100–160 bpm, infants (3–12 months) at 80–140 bpm, and toddlers (1–3 years) at 70–110 bpm. Older children approach the adult 60–100 bpm. A rate of 120 bpm is normal in a 6-month-old but tachycardic in a 10-year-old.

PR interval. It is shorter in children because conduction is faster. Infants measure 0.08–0.14 s, children 0.10–0.16 s, and adolescents reach the adult 0.12–0.20 s. Don’t apply the adult threshold to a child under 12. The chart below plots both sets of bands on one scale.

QRS duration. The QRS is narrow in children, and its upper limits are lower than in adults. Infants stay under 0.08 s, children under 0.09 s, and adolescents under 0.10 s, close to the adult 0.10–0.11 s. A QRS of 0.10 s is borderline in an adult but prolonged in a 5-year-old.

QT interval. It depends heavily on age and rate in children. Infants have relatively longer QT intervals, with QTc up to 440 ms, and the interval shortens progressively through childhood. Adolescents approach the adult QTc limits of about 450 ms in men and 470 ms in women. Always correct the QT before comparing a child’s value.

A full pediatric reference should give each age band its own table. Pair it with a pediatric vital signs chart so heart rate, breathing and blood pressure are judged against the same age band.

How Pabau keeps ECG findings with the patient record

In many practices, ECG findings end up scattered. Some sit in a free-text note, some on a scanned printout, and some on a paper form filed with the tracing. Comparing this year’s QTc with last year’s then means digging through all three.

Pabau, the practice management platform behind our software for GP practices, lets you build your own ECG form in its digital forms builder. Add a field for rate, rhythm, PR interval, QRS duration, QTc and axis, and the completed form is saved to the patient record.

The next clinician sees the previous intervals before reading a new tracing. If you prefer to dictate your interpretation, Pabau Scribe, our AI scribe, turns what you say into a clinical note. That way, you aren’t retyping findings at the end of the day.

Keep ECG findings in one patient record

Build custom forms and clinical notes in Pabau to record ECG findings, intervals and interpretations your way. Each entry stays on the patient record, ready for audits and follow-up.

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Conclusion

Use the chart as a first filter. A value outside its range shows you where to look, and the patient’s history, symptoms and prior tracings tell you what it means.

Two habits keep it reliable. Check paper speed and calibration before you measure, and compare children only against their own age band. Skipping either one can turn a normal tracing into a false alarm.

Print the chart for the ECG room, and record each reading the same way every time so trends stand out across visits. Pabau lets you record ECG findings in your clinical notes alongside the rest of the patient file. Book a demo to see how it keeps your ECG documentation consistent and audit-ready.

Continue your research

Managing a patient with chest pain? Chest pain nursing care plan structures the assessment, interventions and evaluation for a cardiac presentation.

Need to link heart rate to pump function? Cardiac output equation explains how heart rate and stroke volume combine, with normal ranges.

Monitoring heart rate at rest? Sleeping heart rate chart sets out normal resting ranges by age.

Checking the rest of the vital signs? Normal blood pressure chart lists the reference blood pressure categories to record next to the ECG.

Following up an abnormal ECG with an echo? Normal ejection fraction by age chart gives the reference ranges for reading the result.

Frequently asked questions