Fluid Balance Calculator
Log all fluid intake and output sources to calculate 24-hour net fluid balance. Supports IV fluids, oral intake, urine, drains, and insensible losses. Includes clinical interpretation and exportable documentation.
🌊 Log Fluid Balance
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Fluid Balance Monitoring — Clinical Guide
Fluid balance monitoring is a fundamental aspect of inpatient nursing and clinical care. Accurate 24-hour intake and output (I&O) recording enables detection of fluid overload, dehydration, acute kidney injury, and response to diuretic therapy.
What Counts as Intake
- IV fluids (crystalloids, colloids, blood products)
- Oral fluids and fluid content of food (~500–700 mL/day from solid food)
- Nasogastric, PEG, or enteral feeds
- IV medications dissolved in fluid
- Metabolic water (endogenous — approx. 300 mL/day)
What Counts as Output
- Urine (catheter or self-voided)
- Nasogastric aspirates and vomit
- Wound and surgical drains
- Stool (liquid only)
- Insensible losses — sweat, respiration (~800 mL/day, higher in fever)
Interpreting Net Balance
- Positive balance: Intake exceeds output — risk of fluid overload, pulmonary oedema, hypertension
- Negative balance: Output exceeds intake — risk of dehydration, hypovolaemia, acute kidney injury
- Target in most adults: Balance within ±500 mL/24h, unless specific clinical goals exist
For patients with renal impairment, first assess function with our GFR calculator. For IV fluid management, use our IV drip rate calculator. For diuretic dosing, use our drug dosage calculator.
⚠️ Fluid balance decisions must be made by qualified clinicians with full clinical context. This tool is for documentation and reference only.