Health & Fitness
Anion Gap Calculator
Calculate the serum anion gap to help classify metabolic acidosis.
Preparing your result…
What this calculator does
Calculates Anion Gap Calculator using the formula verified against the cited source.
What your result means
An estimate from the inputs you enter, within the scope stated below — not advice.
Formula
Anion gap = Na − (Cl + HCO3)
The step-by-step working for your own numbers appears with the result above and in the PDF report.
Frequently asked questions
Symbols and assumptions
- Inputs
- The values entered in the fields above
- • Conventional potassium-excluding serum anion gap=Na−(Cl+HCO3), with all concentrations in matching mmol/L or mEq/L for these monovalent ions.
Sources and review
Reviewed 2026-10-18 · Next review 2027-04-18
- • Label potassium-excluding and uncorrected for albumin. Reference interval is laboratory/method-specific; albumin correction requires an additional value. The gap alone is not a complete acid–base diagnosis.
Important limitation
This is an educational estimate based only on the values and formula shown. Verify current rates, rules, units, and professional standards before relying on the result. It is not personalized financial or investment advice.
Quick reference
| Scenario | Sodium (mEq/L) | Chloride (mEq/L) | Bicarbonate (HCO3) (mEq/L) | Anion gap |
|---|---|---|---|---|
| Worked example | 140 | 104 | 24 | 12 mEq/L |
| Half the amounts | 110 | 80 | 12 | 18 mEq/L |
| Double the amounts | 170 | 130 | 40 | 0 mEq/L |
Need the full picture? Get the detailed PDF report with charts, tables, formulas and working steps.
Reviewed 2026-10-18 · Next review 2027-04-18
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