Pediatric Blood Pressure Calculator (percentiles by age, sex and height, 2–17 years)

Understanding the pediatric blood pressure calculator — concept and principle

This calculator compares a child's blood pressure with children of the same sex, age and height, using the US Fourth Report (2004) equations. It shows systolic and diastolic percentiles, the 95th-percentile values for that child and the blood pressure category. Parents and clinicians use it after check-ups.

Percentile for age and height: with the default inputs the result is 80.6 / 77.3 (both below 90th → normal).

How it is calculated

Height z-score from the CDC 2000 charts: z = ((height ÷ M)^L − 1) ÷ (L × S)

Expected BP μ = α + Σ βⱼ (age − 10)ʲ + Σ γₖ (z_height)ᵏ, for j, k = 1–4

BP z-score = (measured − μ) ÷ σ, with σ = 10.7128 (boys' systolic), 11.6032 (boys' diastolic), 10.4855 (girls' systolic), 10.9573 (girls' diastolic)

Categories (2004): normal below the 90th percentile; prehypertension 90th to below 95th, or 120/80 mmHg or more; stage 1 from the 95th to the 99th percentile + 5 mmHg; stage 2 above that, using whichever of systolic or diastolic is higher.

The principle

Blood pressure rises naturally as children grow, and taller children of the same age have slightly higher pressure. Regression equations fitted to large US surveys describe the expected pressure for each combination of age, sex and height, and the spread around it. Expressing a reading as a z-score and percentile shows how unusual it is for that particular child.

Worked example

Default inputs: boy, 10 years, 140 cm, 112/70 mmHg.

Height percentile = 58.3 (z ≈ 0.21).
Systolic percentile = 80.6 (z ≈ 0.86, so μ ≈ 112 − 0.86 × 10.71 ≈ 102.7 mmHg).
Diastolic percentile = 77.3 (z ≈ 0.75, so μ ≈ 61.3 mmHg).
95th percentile for this child: systolic 120, diastolic 80 mmHg.
Both below the 90th percentile → Normal blood pressure range.

How to read the result

Where does your result fall?

Readings at or above the 90th percentile deserve repeat measurement. A diagnosis of high blood pressure needs high readings on three separate visits with the right cuff size. The 2017 American Academy of Pediatrics guideline uses newer tables that exclude children with overweight, so its thresholds are a few mmHg lower, and it uses adult cut-offs from age 13.

Common mistakes

Using a cuff that is too small, which falsely raises readings.
Measuring right after activity or while the child is upset.
Diagnosing hypertension from a single reading.

Keep in mind: This is not a diagnosis. Discuss your child's blood pressure with a doctor.

Frequently asked questions

What is a normal blood pressure for a 10-year-old?

It depends on sex and height; below the 90th percentile for that child is normal.

Why does height matter?

Taller children have slightly higher normal pressures at the same age.

Which guideline does my clinic use?

Many now use the 2017 AAP tables; ask which one your doctor follows.

Sources: National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents, "The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents", Pediatrics 2004;114(2 Suppl 4th Report):555–576 · Flynn JT et al., "Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents", Pediatrics 2017;140(3):e20171904

Checked 9 Nov 2026. National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents, “The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents”, Pediatrics 2004;114(2 Suppl 4th Report):555–576 — regression coefficients and category rules as implemented in the MSD Manual medical calculators “Blood Pressure Percentiles for Boys/Girls (2–17 years)”; height z-score from CDC 2000 stature-for-age LMS (Kuczmarski RJ et al., Vital Health Stat 11(246), 2002). Newer thresholds: Flynn JT et al., AAP Clinical Practice Guideline, Pediatrics 2017;140(3):e20171904.

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