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Bicarbonate Deficit Calculator

Work out bicarbonate deficit instantly with clear inputs, formula shown and shareable results.

About Bicarbonate Deficit Calculator

Multiplies the bicarbonate distribution space by body weight and the bicarbonate gap to estimate the millimoles needed for full or half correction.

Formula

Bicarbonate deficit

Deficit (mmol) = distribution factor x weight (kg) x (target HCO3 - measured HCO3), factor 0.4-0.5 rising in severe acidaemia

Worked example

With the default values below, Bicarbonate Deficit Calculator returns Bicarbonate deficit of 280. Change any input above and every figure here is recalculated in your browser.

Inputs used

Body weightaccepts 2–250 kg
70 kg
Current bicarbonateaccepts 2–30 mmol/L
12 mmol/L
Target bicarbonateaccepts 8–30 mmol/L
20 mmol/L
Bicarbonate distribution factoraccepts 0.2–0.8
0.5

Results

Bicarbonate deficit
280 mmol
Half correction dose
140 mmol
50 mmol ampoules required
5.60

Step by step

  1. 1Values used
  2. 2Bicarbonate deficit
  3. 3Bicarbonate deficit= 280 mmol
  4. 4Half correction dose= 140 mmol
  5. 550 mmol ampoules required= 5.60

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

Why give only half?

Half correction limits the risk of overshoot alkalosis, hypokalaemia and paradoxical intracellular acidosis.

Does the factor change?

Yes. The apparent space widens as bicarbonate falls, so factors up to 0.8 are used in severe acidaemia.

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