Calculator Inputs
Use the responsive calculator grid below. It shows three columns on large screens, two on medium screens, and one on mobile.
Example Data Table
This sample demonstrates a 24-hour adult review using example figures.
| Category | Example Value | Unit | Notes |
|---|---|---|---|
| Baseline Weight | 70 | kg | Used for maintenance, urine rate, and balance per kg. |
| Review Duration | 24 | hours | One full day shift review. |
| Total Intake | 3200 | mL | Oral, IV, blood, feeds, and flushes combined. |
| Total Output | 2900 | mL | Urine, stool, drains, blood, emesis, and insensible loss. |
| Net Balance | +300 | mL | Positive but relatively small. |
| Urine Output | 1800 | mL | Equals about 1.07 mL/kg/hr over 24 hours. |
| Maintenance Requirement | 2500 | mL/24h | Estimated by Holliday-Segar method. |
| Fluid Overload Approx. | 0.43 | % | Based on net balance and baseline weight. |
Formula Used
1) Total Intake
Total Intake = Oral + IV Crystalloid + IV Colloid + Blood Products + Enteral Feed + Medication/Flushes + Other Intake
2) Total Output
Total Output = Urine + Emesis + Stool/Ostomy + Drains + Blood Loss + Insensible Loss + Other Output
3) Net Fluid Balance
Net Balance = Total Intake − Total Output
4) Net Balance per Kilogram
Net Balance per kg = Net Balance ÷ Weight (kg)
5) Urine Output Rate
Urine Output Rate = Urine Output (mL) ÷ [Weight (kg) × Hours]
6) Maintenance Requirement
24-hour maintenance uses the Holliday-Segar method:
• First 10 kg: 100 mL/kg/day
• Second 10 kg: 50 mL/kg/day
• Each kg above 20 kg: 20 mL/kg/day
Maintenance for selected period = 24-hour maintenance × (Hours ÷ 24)
7) Fluid Overload Approximation
Fluid Overload % ≈ Net Balance (mL) ÷ [Baseline Weight (kg) × 10]
This is a balance-based approximation. It should not replace validated clinical definitions or local policy.
How to Use This Calculator
- Enter the patient’s baseline or admission weight in kilograms.
- Optionally add current weight to compare weight change and weight-based overload.
- Choose the charting period, such as 8, 12, or 24 hours.
- Set the urine output target in mL/kg/hr for your review context.
- Fill in all measurable intake volumes for the selected period.
- Fill in output volumes, then add insensible loss only if you want an estimate included.
- Click Calculate Fluid Balance to show results above the form.
- Use the CSV and PDF buttons to export a quick summary for teaching, chart review, or internal documentation.
FAQs
1) What does this fluid balance calculator measure?
It totals recorded intake and output, then estimates net balance, urine output rate, maintenance requirement, and a simple balance-based overload percentage for the chosen review period.
2) Why is insensible loss optional?
Insensible loss is harder to measure directly. It changes with fever, ventilation, burns, ambient conditions, and clinical context. Some teams include an estimate, while others review it separately.
3) Is a positive fluid balance always harmful?
No. Context matters. A positive balance may be expected during resuscitation or transfusion. The result still needs interpretation alongside vital signs, labs, exam findings, and treatment goals.
4) What urine output target should I enter?
Use the target relevant to your setting, patient population, and protocol. Many adult reviews use 0.5 mL/kg/hr, but local standards and patient factors can differ.
5) Can I use this for pediatrics?
Yes, but only with care. The maintenance formula supports weight-based estimates, yet pediatric targets and interpretations vary widely. Always verify with pediatric guidance and local policy.
6) Does this replace bedside charting or an EHR?
No. It is best used as a calculation aid, review tool, or teaching support. Official records should remain in your validated charting system and follow institutional policy.
7) Why compare intake with maintenance requirement?
That comparison helps show whether recorded intake is below, near, or above a simple daily requirement estimate. It supports review but does not determine what the patient should receive.
8) What do the CSV and PDF buttons export?
They export the calculated summary plus intake and output breakdowns from your submitted values. This is useful for internal review, teaching notes, or quick handoff documentation.