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Adult Maintenance Fluids 4-2-1 Rule Calculator

4 mL/kg/h first 10 kg + 2 mL/kg/h next 10 + 1 mL/kg/h thereafter.

Calculates hourly and daily IV maintenance fluid rates for adults using the 4-2-1 rule based on body weight.

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Priya Venkatesan By Priya Venkatesan
Published Last reviewed 1 min read

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Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

≤10 kg: 4 mL/kg/h; 11–20 kg: 40 + 2×(w−10); >20 kg: 60 + 1×(w−20)

In depth

Calculates hourly and daily IV maintenance fluid rates for adults using the 4-2-1 rule based on body weight.