# Anion Gap Calculator

URL: https://speedycalculator.com/calculators/health/anion-gap/
Last updated: 2026-10-25

> The anion gap calculator estimates unmeasured anions in blood from sodium, chloride and bicarbonate, with an optional albumin correction. It helps classify metabolic acidosis.

## Inputs

- Sodium (mEq/L)
- Chloride (mEq/L)
- Bicarbonate (mEq/L)
- Albumin (g/dL)

## Results

- Anion gap
- Albumin-corrected anion gap

## Formula

```
Anion gap = Na⁺ − (Cl⁻ + HCO₃⁻)
Albumin-corrected AG = AG + 2.5 × (4.0 − albumin g/dL)
```

## Explanation

A raised anion gap points toward causes such as ketoacidosis, lactic acidosis or toxins.

### How to use the Anion Gap Calculator

- **Sodium**
- **Chloride**
- **Bicarbonate**
- **Albumin**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Subtract chloride and bicarbonate from sodium. Low albumin lowers the gap, so a correction is added.

### Inputs explained

FieldWhat to enterSodiumIn mEq/LChlorideIn mEq/LBicarbonateIn mEq/LAlbuminIn g/dL

### What each result means

- **Anion gap** = [Sodium] - ([Chloride] + [Bicarbonate])
- **Albumin-corrected anion gap** = [Anion gap] + 2.5×(4 - [Albumin])

*Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.*

## Worked example

Inputs — Sodium: 140 mEq/L; Chloride: 104 mEq/L; Bicarbonate: 24 mEq/L; Albumin: 4 g/dL.

Results — **Anion gap = 12 mEq/L**; Albumin-corrected anion gap = 12 mEq/L.

## FAQ

**What is a normal anion gap?**
Commonly about 3–12 mEq/L without potassium, but ranges vary between laboratories.

**Should potassium be included?**
Some labs add potassium, which raises the normal range by about 4.

**What formula does the Anion Gap Calculator use?**
Anion gap = Na⁺ − (Cl⁻ + HCO₃⁻).


## Sources

- [Kraut JA, Madias NE. Serum anion gap: its uses and limitations in clinical medicine. Clin J Am Soc Nephrol, 2007](https://pubmed.ncbi.nlm.nih.gov/17699401/)