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Paediatric Maintenance Fluid Calculator

Calculate pediatric maintenance IV fluid rates using the Holliday-Segar method (4-2-1 rule). Enter a child's weight in kg to find the hourly rate (mL/hr) and daily volume (mL/day). The 4-2-1 rule gives 4 mL/kg/hr for the first 10 kg, 2 mL/kg/hr for the next 10 kg, and 1 mL/kg/hr for each additional kg above 20 kg. Used by pediatricians, nurses, and emergency physicians worldwide.

Enter Values

Weight (kg)

Result

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Formula

Core Formula

\text{Rate} = \underbrace{4 \times 10}_{\text{first 10 kg}} + \underbrace{2 \times 10}_{\text{next 10 kg}} + \underbrace{1 \times (W - 20)}_{\text{remaining}} \; \text{mL/hr}

How it works: The Holliday-Segar formula (published 1957) estimates metabolic water requirements based on caloric expenditure at different body weights. The 4-2-1 shorthand calculates hourly rates; the equivalent 100-50-20 rule calculates daily volumes. Both produce the same total.

Worked Example

A 25 kg child needs maintenance fluids:

1Step 1: First 10 kg at 4 mL/kg/hr = 10 x 4 = 40 mL/hr

2Step 2: Next 10 kg at 2 mL/kg/hr = 10 x 2 = 20 mL/hr

3Step 3: Remaining 5 kg at 1 mL/kg/hr = 5 x 1 = 5 mL/hr

4Step 4: Total hourly rate = 40 + 20 + 5 = 65 mL/hr

5Step 5: Daily volume = 65 x 24 = 1,560 mL/day

Result: 65 mL/hr or 1,560 mL/day of D5 0.45% NaCl with 20 mEq/L KCl

Pediatric Maintenance Fluid Calculator - 4-2-1 Rule

The Holliday-Segar formula, published in 1957, remains the standard method for calculating maintenance IV fluid rates in pediatrics. It estimates water requirements based on metabolic rate at different body weights.

First 10 kg of body weight: 4 mL/kg/hr (100 mL/kg/day). A 10 kg infant needs 40 mL/hr or 1,000 mL/day
Next 10 kg (11-20 kg): 2 mL/kg/hr (50 mL/kg/day). A 20 kg child needs 40 + 20 = 60 mL/hr or 1,500 mL/day
Each additional kg above 20: 1 mL/kg/hr (20 mL/kg/day). A 25 kg child needs 40 + 20 + 5 = 65 mL/hr or 1,560 mL/day
Standard maintenance fluid: D5 0.45% NaCl with 20 mEq/L KCl for most children. Neonates may require D10 with lower sodium
Adjust for fever (+10-12% per degree C above 37), burns (use Parkland formula instead), and cardiac or renal conditions (restrict to 2/3 maintenance)

The Holliday-Segar method provides baseline fluid requirements only. Always adjust for clinical context including fever, surgical losses, ongoing losses (vomiting, diarrhea), and underlying conditions. This calculator is for educational reference only.

You can also calculate changes using our Paediatric Weight Estimation Calculator, Dosage Calculator, Burn Surface Area and Parkland Formula or Paediatric Dosage Calculator.

Holliday-Segar Quick Reference: Maintenance Fluid Rates by Weight

Pre-calculated maintenance IV fluid rates using the 4-2-1 rule for common pediatric and adult weights.

Weight (kg)	mL/hr	mL/day	Calculation
5 kg	20	500	5 x 4 = 20
8 kg	32	800	8 x 4 = 32
10 kg	40	1,000	10 x 4 = 40
12 kg	44	1,100	40 + (2 x 2) = 44
15 kg	50	1,250	40 + (5 x 2) = 50
20 kg	60	1,500	40 + (10 x 2) = 60
25 kg	65	1,560	40 + 20 + (5 x 1) = 65
30 kg	70	1,700	40 + 20 + (10 x 1) = 70
40 kg	80	1,900	40 + 20 + (20 x 1) = 80
50 kg	90	2,100	40 + 20 + (30 x 1) = 90
60 kg	100	2,400	40 + 20 + (40 x 1) = 100
70 kg	110	2,500 (capped)	40 + 20 + (50 x 1) = 110

Note: Rates shown are for baseline maintenance without adjustments. Add 10-12% per degree Celsius of fever. Restrict to 2/3 maintenance for cardiac or renal patients. Maximum daily volume is typically capped at 2,400-2,500 mL/day. For educational reference only.

Frequently Asked Questions

What is the Holliday-Segar formula for maintenance fluids?

The Holliday-Segar formula (also called the 4-2-1 rule) calculates maintenance IV fluid rates based on body weight: 4 mL/kg/hr for the first 10 kg, 2 mL/kg/hr for the next 10 kg, and 1 mL/kg/hr for each kg above 20. For a 25 kg child: (10 x 4) + (10 x 2) + (5 x 1) = 65 mL/hr or 1,560 mL/day.

How does the 4-2-1 rule work for a 15 kg child?

For 15 kg: first 10 kg at 4 mL/kg/hr = 40 mL/hr, next 5 kg at 2 mL/kg/hr = 10 mL/hr. Total = 50 mL/hr or 1,200 mL/day. The daily equivalent uses the 100-50-20 rule: (10 x 100) + (5 x 50) = 1,250 mL/day (slight rounding difference from hourly calculation).

What fluid type is used for pediatric maintenance?

The most common maintenance fluid is D5 0.45% NaCl (dextrose 5% in half-normal saline) with 20 mEq/L of potassium chloride added. Some protocols use D5 0.9% NS (normal saline) for post-operative patients. Neonates typically receive D10 with lower sodium concentrations. Always follow your institution's protocol.

When should maintenance fluids be adjusted?

Increase by 10-12% per degree Celsius of fever above 37C. Post-operative patients may need 1.5x maintenance. Restrict to 2/3 maintenance for cardiac failure, renal insufficiency, or SIADH. Burns over 15-20% TBSA require the Parkland formula instead of standard maintenance calculations.

Does the Holliday-Segar formula work for adults?

Yes. The 4-2-1 rule applies to any weight. A 70 kg adult: (10 x 4) + (10 x 2) + (50 x 1) = 110 mL/hr or 2,640 mL/day. Daily maintenance is often capped at 2,400-2,500 mL/day for patients over 70-80 kg to prevent fluid overload.

Does this calculator include fluid replacement for dehydration?

No. This calculates maintenance (baseline) fluid needs only. Dehydrated patients need additional replacement fluids calculated separately based on the degree of dehydration (mild 5%, moderate 10%, severe 15% of body weight). Ongoing losses from vomiting, diarrhea, or surgical drains must also be replaced on top of maintenance.

How do I add this Paediatric Maintenance Fluid Calculator to my site?

Absolutely. Use the "Embed" option above to tailor the dimensions, color scheme, and styling to match your site. Copy the generated iframe snippet and drop it into your HTML, WordPress editor, or any CMS. There is no cost and no account required. See calculory.com/services/embed-calculators for a step-by-step walkthrough.

Medical Disclaimer

This calculator is provided for informational and educational purposes only. It is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any decisions based on these results. Do not disregard or delay seeking medical advice because of information obtained from this tool.

AI Assistant

Ask about this calculator

I can help you understand the paediatric maintenance fluid calculator formula, interpret your results, and answer follow-up questions.

Try asking

Our AI assistant provides general estimates and advice only. Please consult a qualified healthcare professional before making any health-related decisions.

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Paediatric Weight Estimation Calculator Dosage Calculator Burn Surface Area and Parkland Formula Paediatric Dosage Calculator

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