Calculator form
Example data table
| Scenario | Patient group | Weight | Dehydration | Ongoing losses | Bolus | Deficit window |
|---|---|---|---|---|---|---|
| General adult replacement | Adult | 70 kg | 5% | 300 mL/24h | 10 mL/kg | 24 hours |
| Pediatric dehydration estimate | Pediatric | 18 kg | 6% | 150 mL/24h | 20 mL/kg | 48 hours |
| High loss monitoring case | Adult | 82 kg | 4% | 900 mL/24h | 0 mL/kg | 24 hours |
Formula used
Adult maintenance: Weight (kg) × selected adult maintenance rate (mL/kg/day)
Pediatric maintenance: 100 mL/kg/day for the first 10 kg, 50 mL/kg/day for the next 10 kg, and 20 mL/kg/day above 20 kg
Hourly pediatric equivalent: 4-2-1 rule
Estimated dehydration deficit: Weight (kg) × dehydration (%) × 10
Deficit hourly replacement: Deficit ÷ replacement hours
Base hourly rate: Maintenance hourly + ongoing losses hourly + additional replacement hourly
Active hourly rate: Base hourly rate + deficit hourly replacement
First 24-hour total: Bolus + maintenance day + ongoing losses + additional replacement + deficit portion delivered in 24 hours
This page calculates fluid volumes and rates only. Fluid composition, sodium, potassium, glucose, and monitoring frequency should follow clinical assessment and local protocol.
How to use this calculator
- Select whether the case is adult or pediatric.
- Enter body weight in kilograms.
- Choose the adult maintenance rate if adult mode is selected.
- Enter the estimated dehydration percentage.
- Add any ongoing abnormal losses expected over 24 hours.
- Add any extra clinician-planned replacement volume if needed.
- Choose any initial bolus in mL/kg.
- Select how many hours you want the deficit spread across.
- Submit the form to see maintenance, deficit, hourly rates, totals, graph, and export options.
FAQs
1. Does this calculator work for both adults and children?
Yes. Adult mode uses a selected daily mL/kg maintenance rate. Pediatric mode uses the Holliday-Segar maintenance method and shows the equivalent hourly rate automatically.
2. Can this tool replace a formal IV prescription?
No. It estimates volumes and rates. Final prescribing still depends on diagnosis, blood pressure, perfusion, sodium, potassium, glucose, renal function, urine output, and local policy.
3. Why is pediatric maintenance different from adult maintenance?
Children have different fluid needs relative to body weight. Pediatric maintenance commonly follows the Holliday-Segar approach rather than a single adult-style mL/kg/day rate.
4. What does dehydration percentage mean here?
It is an estimated body water deficit percentage. The calculator converts that estimate into milliliters using weight and a simple deficit equation.
5. Are ongoing losses included in the final answer?
Yes. Ongoing losses entered as mL per 24 hours are added into the daily total and converted into an hourly replacement contribution.
6. Why is the bolus shown separately?
A bolus is often delivered rapidly for immediate volume support. Keeping it separate helps distinguish urgent resuscitation volume from slower maintenance and deficit replacement.
7. When should these outputs be used very cautiously?
Use caution in shock, sepsis, renal failure, heart failure, pregnancy, burns, major bleeding, hypernatremia, DKA, severe electrolyte imbalance, or when labs are changing quickly.
8. Can I save the results for documentation?
Yes. After calculation, you can export a CSV summary or generate a PDF report containing the key fluid values and schedule checkpoints.