- Enter the child's weight in kg (required — this is what converts a percent-loss estimate into an actual fluid-deficit volume in mL).
- Choose the scale you want to use: the WHO Plan A/B/C 3-sign field tool, or the validated Gorelick 10-point ED clinical scale.
- Tick every clinical finding the child has. The severity category and estimated percent dehydration update on every change.
- Read off the estimated fluid deficit (mL) and the recommended oral (ORS) or IV replacement plan in the result panel.
All computation runs in your browser; no values are stored or transmitted.
When to Use
Use this tool at the bedside or in the emergency department in any child with acute fluid losses — acute gastroenteritis, prolonged vomiting, fever with poor intake, heat illness, or burns — to put a defensible severity category and an actual deficit volume on a vague clinical impression. It is the first decision in pediatric resuscitation: is this an "ORS at home" child, a "monitored ORS Plan B" child, or a "call the team, give isotonic fluid now" child?
Appropriate population
Infants, toddlers, and children with acute or subacute volume loss whose dehydration severity must be classified at first contact. Both scales were developed for previously well children with diarrheal or vomiting illnesses; the WHO scheme is the universal field/primary-care tool, while the Gorelick scale was validated in a US pediatric ED. The deficit calculation (% dehydration × weight × 10) applies once a severity band is chosen.
When NOT to rely on it
Clinical scales overestimate dehydration in neonates < 1 month, in malnourished children (severe acute malnutrition has its own WHO algorithm — fluid is given more cautiously), and in chronic / slowly accumulating losses where the body adapts. They are also unreliable when a measured pre-illness weight is available — that actual weight loss is more accurate than any clinical score. Hypernatremic dehydration (serum Na > 150 mmol/L) requires slower, not faster, correction (drop Na by ≤ 10 mEq/L/24 h) to avoid cerebral edema, and frank shock requires immediate 20 mL/kg isotonic boluses regardless of the score.
Pearls & Pitfalls
Three signs do the WHO heavy lifting
The WHO 4th-revision algorithm is deliberately simple — mental status, eye appearance, how the child drinks, and skin pinch recoil. Two or more "moderate" signs put the child in Some dehydration (Plan B); two or more "severe" signs (lethargy, very sunken eyes, drinks poorly or cannot drink, very slow skin pinch > 2 s) put the child in Severe dehydration (Plan C). You do not need labs to triage with this scheme.
Gorelick has the best test characteristics
Gorelick's 10-point scale has the strongest published validation in a pediatric ED: a score of ≥ 3 is ~ 87% sensitive and 82% specific for ≥ 5% dehydration; ≥ 6 / 10 identifies severe (≥ 10%) dehydration. The most useful individual findings are prolonged capillary refill > 2 s, abnormal skin turgor, and abnormal respiratory pattern — when any of these three are present the post-test probability of clinically important dehydration jumps sharply.
Pitfalls
(1) Dehydration percent is always an estimate; the gold standard remains measured acute weight loss when a pre-illness weight is known. (2) Tachycardia and absent tears are non-specific in a febrile or crying child and over-call dehydration. (3) Avoid hypotonic maintenance fluids in acutely ill children (AAP 2018) — use isotonic crystalloid (0.9% NS or LR) for boluses and as the maintenance base to prevent hospital-acquired hyponatremia. (4) In hypernatremic dehydration correct slowly — aim Na drop ≤ 10 mEq/L per 24 h to avoid cerebral edema. (5) Severe dehydration with persistent shock after 60 mL/kg of crystalloid in the first hour should prompt escalation (ICU, vasopressors, search for sepsis/cardiac dysfunction), not more boluses by reflex.
Why Use It
Acute dehydration is the leading cause of preventable death from gastroenteritis in children worldwide, and under-recognition is the single most common contributor to bad outcomes. A structured score does two things at once: it converts a soft clinical impression ("looks dry") into a defensible severity band that drives the right fluid plan, and it generates an estimated volume of deficit you can write an actual order for. The WHO scheme is the standard for outpatient and primary-care triage; the Gorelick scale is the best-validated bedside tool in the emergency department. Using either consistently — and pairing the severity band with the correct ORS or IV plan — is what prevents both under-resuscitation (shock, AKI) and over-resuscitation (iatrogenic hyponatremia, cerebral edema from too-rapid correction of hypernatremic dehydration).
Pediatric Dehydration — Severity & Fluid Deficit
Enter the child's weight, choose a scale (WHO Plan A/B/C or Gorelick 10-point), and tick every clinical finding present. The severity category, estimated fluid deficit (mL), and recommended replacement plan update on every change.
⚕ WHO 2005 (Treatment of Diarrhoea, 4th rev.); Gorelick MH et al. Pediatrics 1997;99(5):E6; Steiner MJ et al. JAMA 2004;291(22):2746–2754. Severity scales are estimates; measured acute weight loss remains the gold standard. Use isotonic crystalloid (0.9 % NS or LR) for boluses (AAP 2018). In hypernatremic dehydration (Na > 150 mmol/L), correct slowly — aim Na drop ≤ 10 mEq/L per 24 h — to prevent cerebral edema. For licensed clinicians; not a substitute for individualized assessment.
Next Steps
Translate the severity band into a concrete fluid plan and disposition.
- No / mild dehydration (< 5 %, Plan A) — manage at home with ORS after each loose stool (≈ 10 mL/kg per stool, 2 mL/kg per emesis) and continued age-appropriate feeding. Safety-net for return: refusal to drink, persistent vomiting, lethargy, no urine for 8 h, blood in stool.
- Moderate dehydration (5–9 %, Plan B) — give ORS 75 mL/kg over 4 hours under observation; reassess every hour. If oral fails (intractable vomiting, ileus, altered sensorium), replace the deficit + maintenance + ongoing losses over 24 h IV (half the deficit in the first 8 h, half over the next 16 h).
- Severe dehydration (≥ 10 %, Plan C / shock) — immediate IV access (or IO) and isotonic bolus 20 mL/kg NS or LR over 15–30 min, repeat up to 60 mL/kg in the first hour as needed; then replace deficit + maintenance + losses over 24 h. WHO Plan C age-specific schedule: in children ≥ 1 y give 30 mL/kg over 30 min then 70 mL/kg over 2.5 h; in infants < 1 y the same volumes over 1 h then 5 h. Admit; consider sepsis if shock persists past 60 mL/kg.
- Check serum Na, K, glucose, urea/creatinine, venous gas before/during IV resuscitation. In hypernatremic dehydration (Na > 150) replace deficit over 48–72 h, aim Na drop ≤ 10 mEq/L per 24 h, and avoid hypotonic fluids — cerebral edema is the feared complication.
- Pair this with Holliday–Segar maintenance fluids and the insensible water loss calculator to write the full 24-hour IV order.
Evidence & References
WHO Plan A / B / C — severity bands
| Category | Signs | % loss | Plan |
|---|---|---|---|
| No dehydration | None of the moderate / severe signs | < 5 % | Plan A — home ORS |
| Some dehydration | ≥ 2 moderate signs (restless, sunken eyes, thirsty, skin pinch slow) | 5–10 % | Plan B — ORS 75 mL/kg over 4 h |
| Severe dehydration | ≥ 2 severe signs (lethargic, very sunken eyes, drinks poorly, pinch > 2 s) | > 10 % | Plan C — IV: 30 mL/kg then 70 mL/kg (≥ 1 y over 30 min + 2.5 h; < 1 y over 1 h + 5 h) |
Gorelick 10-point scale — score → severity
| Score (out of 10) | % dehydration | Category |
|---|---|---|
| 0–2 | < 3 % | None / mild |
| 3–5 | 5–9 % | Moderate |
| 6–10 | ≥ 10 % | Severe |
Fluid deficit & replacement
| Quantity | Formula / rule |
|---|---|
| Estimated fluid deficit (mL) | % dehydration × weight (kg) × 10 |
| Moderate (5 %) | ORS 75 mL/kg over 4 h, OR IV: half deficit in 8 h, half over next 16 h, plus maintenance |
| Severe (≥ 10 %) | IV bolus 20 mL/kg NS / LR, repeat up to 60 mL/kg in the first hour; then deficit + maintenance + losses over 24 h |
| Hypernatremic (Na > 150) | Replace deficit over 48–72 h; aim Na drop ≤ 10 mEq/L per 24 h |
The WHO scheme is the universal triage tool used worldwide in primary care and humanitarian settings. The Gorelick scale was prospectively derived and validated in a US pediatric ED (a score ≥ 3 is ~ 87 % sensitive and 82 % specific for ≥ 5 % dehydration). Both estimate volume status; measured acute weight loss remains the gold standard whenever a pre-illness weight is available.
References
- World Health Organization. The Treatment of Diarrhoea: A manual for physicians and other senior health workers. 4th rev. Geneva: WHO; 2005.
- Gorelick MH, Shaw KN, Murphy KO. Validity and reliability of clinical signs in the diagnosis of dehydration in children. Pediatrics. 1997;99(5):E6. doi:10.1542/peds.99.5.e6.
- Steiner MJ, DeWalt DA, Byerley JS. Is this child dehydrated? JAMA. 2004;291(22):2746–2754. doi:10.1001/jama.291.22.2746.
