Which Pediatric Calculator to Use When
A bedside index of every calculator on TinyHumanMD: what it answers, the population it applies to, and the guideline or paper it follows. Each population limit below is taken from the calculator's own page and its verified clinical spec. Updated September 2026.
Most bedside errors with clinical scores are not arithmetic — they are applying a score outside the population it was derived in. Every tool below states its population explicitly. If your patient falls outside it, the number is not interpretable, and the page will say so.
Immunizations
| Calculator | Answers | Population | Follows |
|---|---|---|---|
| Catch-Up Immunization Schedule | What is due now and next for a child behind on vaccines, applying minimum ages and intervals | Children and adolescents, birth to 18 years | CDC/ACIP General Best Practice Guidelines, harmonized with the AAP |
Background reading: Catch-Up Immunization: Getting a Child Back on Schedule.
Newborn and NICU
| Calculator | Answers | Population | Follows |
|---|---|---|---|
| Newborn Bilirubin (AAP 2022) | Hour-specific phototherapy and exchange transfusion thresholds, plus follow-up timing | Newborns ≥ 35 weeks gestation | AAP 2022 Clinical Practice Guideline for hyperbilirubinemia |
| Gestational Age & Corrected Age | Gestational age, corrected (adjusted) age and estimated due date from LMP or EDD | Preterm and term infants | AAP / ACOG dating conventions |
| New Ballard Score | Gestational age estimated from physical exam when dating is unavailable | Newborns, 20–44 weeks | Ballard JL et al. J Pediatr 1991 |
| APGAR Score | Newborn condition at 1 and 5 minutes across five components, with interpretation bands | Newborns at delivery | Apgar V. Curr Res Anesth Analg 1953 |
| Early-Onset Sepsis (approximate) | Approximate EOS risk from maternal risk factors, GBS status and clinical exam tier | Newborns ≥ 34 weeks gestation | Escobar 2014 / Kuzniewicz 2017 — simplified; links to the canonical Kaiser tool |
Background reading: Newborn Jaundice and the AAP 2022 Bilirubin Thresholds.
Growth and vitals
| Calculator | Answers | Population | Follows |
|---|---|---|---|
| Growth Percentiles | Percentiles and Z-scores for weight, length/height, head circumference and BMI | WHO 0–24 months; CDC 2–20 years; Fenton 2025 and Olsen 2010 (23–41 weeks) for preterm | WHO and CDC growth charts; Fenton 2025; Olsen 2010 |
| Blood Pressure Percentile | Normal, elevated, Stage 1 or Stage 2 hypertension by age, sex and height | Children and adolescents; adolescents ≥ 13 years use the adult thresholds. Height-50th-percentile model only | AAP 2017 Clinical Practice Guideline (Flynn et al.) |
| Mid-Parental Target Height | Target adult height from both parents' heights, with the ±8.5 cm expected range | Children whose biological parents' heights are both known | Tanner, Goldstein & Whitehouse 1970 (Arch Dis Child) |
Background reading: Pediatric Growth Charts: WHO vs CDC vs Fenton.
Emergency and decision rules
| Calculator | Answers | Population | Follows |
|---|---|---|---|
| PECARN Head Injury Rule | Whether head CT, observation or discharge is indicated after blunt head trauma | Two strata: children < 2 years and 2–18 years | Kuppermann N et al. Lancet 2009 |
| UTI Risk (approximate) | Pre-test probability of urinary tract infection before urine testing | Febrile children 2–24 months | Shaikh 2018 (JAMA Pediatr) — simplified; links to the canonical UTICalc |
| Centor / McIsaac Score | Pre-test probability of group A strep pharyngitis and whether to do a rapid test | Patients with sore throat; the McIsaac age modifier spans 3–14, 15–44 and ≥ 45 years | McIsaac WJ et al. CMAJ 1998 |
| Westley Croup + PRAM Asthma | Severity grade and management band for croup or acute asthma | Children with croup (Westley) or acute asthma (PRAM) | Westley CR et al. 1978; Chalut DS et al. J Pediatr 2000 |
| RDAI Bronchiolitis Score | Bronchiolitis severity from wheezing and retractions, scored 0–17 | Infants with bronchiolitis | Lowell DI et al. Pediatrics 1987 |
| Pediatric GCS + FOUR Score | Level of consciousness on two scales side by side | Children; the verbal scale differs for age < 2 years and ≥ 2 years | Teasdale & Jennett 1974 (Lancet); Wijdicks EFM et al. 2005 |
| Epinephrine + Broselow | IM epinephrine dose (0.01 mg/kg), auto-injector strength, and weight estimated from length | Children in anaphylaxis; auto-injector 0.3 mg at ≥ 30 kg; Broselow estimates weight by length | Sicherer SH et al. Pediatrics 2017; Broselow tape |
| Wong-Baker FACES Pain Scale | Self-reported pain intensity on a 0–10 scale with interpretation bands | Children ≥ 3 years who can self-report | Wong DL & Baker CM. Pediatr Nurs 1988 |
Dosing, fluids and renal function
| Calculator | Answers | Population | Follows |
|---|---|---|---|
| Weight-Based Dosing | mg/kg dose and the volume of a given formulation, with per-dose and daily caps | Children with a documented weight | AAP Red Book and standard pediatric dosing references |
| Maintenance IV Fluids | Hourly and daily maintenance, dehydration deficit replacement, and bolus volumes | Children requiring maintenance intravenous fluids | Holliday & Segar 1957 (Pediatrics) 4-2-1 rule; AAP 2018 isotonic fluid guidance |
| eGFR (Bedside Schwartz) | Estimated GFR from height and serum creatinine, with KDIGO CKD staging | Validated in children aged 1–16 years with CKD; less accurate in acute kidney injury, very young infants, or muscle-mass extremes | Schwartz GJ et al. JASN 2009; KDIGO 2024 CKD |
Frequently asked questions
Are these pediatric calculators valid at every age?
No. Each tool states the population it was derived in. The UTI risk score applies to febrile children 2–24 months, the early-onset sepsis model to newborns ≥ 34 weeks, the AAP 2022 bilirubin thresholds to newborns ≥ 35 weeks, and Bedside Schwartz eGFR was validated in children aged 1–16 years with chronic kidney disease. Using a tool outside its derivation population invalidates the result.
Which calculator should I use for a jaundiced newborn?
The Newborn Bilirubin calculator, which applies the AAP 2022 hour-specific phototherapy and exchange thresholds for infants ≥ 35 weeks. Establish gestational age first with the Gestational Age calculator from dating, or the New Ballard Score if dating is unavailable.
Which of these calculators are approximations rather than the original tool?
Two. The early-onset sepsis calculator is a simplified scoring approximation of the Kaiser Permanente regression model, and the UTI risk calculator is a simplified pre-test probability score based on Shaikh 2018. Both pages link to the canonical tool and should not replace it for a documented decision.
Do the calculators work offline?
Yes. Every calculator is static HTML and JavaScript with its reference tables bundled locally and a service worker caching the pages, so each one runs without a network connection. Calculations happen in the browser.
Browse all pediatric calculators →
Sources: each row cites the guideline or primary paper shown on that calculator's own page; population limits are taken from the same pages and from the verified clinical specs behind them. This guide is for clinical decision support and education only — not a substitute for clinical judgment.