Maintenance fluids calculator (Holliday–Segar)
Enter your values. The answer and the full worked solution update as you type.
Result
Hourly rate (4-2-1)64 mL/h
Daily volume (100-50-20)1580 mL/day
The 4-2-1 hourly rule and the 100-50-20 daily rule are two approximations: multiplied by 24, the hourly rule gives less below 35 kg and more above it. Use the method your question names. For exam practice only. This is a study aid, never a clinical decision: always follow the prescription, local protocols and the product information.
Step-by-step solution
Per hour
4·10 + 2·10 + 1·4 = 64 mL/h
Per day
100·10 + 50·10 + 20·4 = 1580 mL/day
Key formulas
- Holliday–Segar per hour
- 4 mL/kg (first 10 kg) + 2 mL/kg (next 10 kg) + 1 mL/kg (each kg above 20)
- Holliday–Segar per day
- 100 / 50 / 20 mL/kg for the same bands
Practise IV fluids & fluid balance
A calculator gives the answer. In the exam you need the method: practise it with new problems, hints and worked solutions.
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