Acid Base Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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When sodium, bicarbonate, osmolality, or an infusion rate is changing, clean arithmetic matters. Acid Base Calculator focuses on the exact variables shown in the tool and returns the estimate its engine supports.

What this calculator does

Acid Base Calculator uses pH, PCO₂, HCO₃⁻, Chloride, Sodium, and Albumin to calculate acid-base assessment. Where supported, it also shows Calculated Henderson–Hasselbalch pH, Anion gap, and Albumin-corrected anion gap so the primary result is easier to check. It follows the exact field flow and engine behavior in this plugin rather than describing a different calculator with the same name. Fluid and electrolyte formulas are sensitive to units, timing, ongoing losses, kidney function, and rapidly changing physiology. They are most useful as structured estimates alongside repeat measurements and bedside assessment.

How to use it

Enter or select pH, PCO₂, HCO₃⁻, Chloride, Sodium, and Albumin. Use the units offered by the calculator and keep paired laboratory or treatment values from the same clinical episode whenever the formula assumes that. If an entry is unknown, do not substitute a guess simply to obtain a number.

How the calculation works

The tool uses the entered pH to label acidemia, alkalemia, or a common-reference-range pH. It also calculates a Henderson–Hasselbalch pH from bicarbonate and PCO₂, an anion gap as sodium − chloride − bicarbonate, and an albumin-corrected anion gap by adding 2.5 × (4 − albumin).

Example

Using the sample values prefilled in this calculator, the primary result is pH in common reference range (Acid-base assessment), Calculated Henderson–Hasselbalch pH is 7.401, and Anion gap is 12 mmol/L. This example demonstrates the plugin’s own calculation path; replace the sample inputs with verified values before interpreting a real result.

How to interpret the result

Use the displayed pattern to organize the blood-gas and electrolyte data, then confirm compensation and the clinical cause. Mixed disorders are common, so a normal-looking pH does not mean acid-base physiology is normal.

Limitations and notes

A full acid-base interpretation may require compensation checks, delta relationships, lactate/ketones, renal function, and the patient’s clinical history. Albumin correction and reference ranges are approximations and should not override a measured blood gas.