Anion Gap Calculator
Calculate the serum anion gap from sodium, chloride, and bicarbonate.
Anion Gap measurements
Enter your values, then calculate.
Result
How to calculate anion gap
The anion gap is a calculated value used in clinical medicine to help identify and classify the cause of metabolic acidosis, based on routine electrolyte panel results.
How the calculation works
Anion gap = Sodium − Chloride − Bicarbonate. All values are typically measured in mEq/L (milliequivalents per liter).
Example
Sodium 140, Chloride 104, Bicarbonate 24 mEq/L: Anion gap = 140 − 104 − 24 = 12 mEq/L, within a commonly cited normal range of roughly 8-12 mEq/L (reference ranges vary by lab).
Frequently asked questions
How is Result calculated?
Result = [Sodium] − [Chloride] − [Bicarbonate].
Is the Anion Gap Calculator free to use?
Yes — every calculator on Simple Calculator Tools is free, runs in your browser, and does not require an account.
Anion Gap Calculator
Anion gap = Sodium − Chloride − Bicarbonate. All values are typically measured in mEq/L (milliequivalents per liter).
Let's understand your anion gap result.
Calculate a result above and this guide will help you interpret it using this calculator's own formula and explanation.
Pro Tips for Anion Gap
- Normal anion gap reference ranges vary somewhat by laboratory and testing method — always check against the specific lab's stated reference range.
- An elevated anion gap can help point toward specific causes of metabolic acidosis, but interpretation should always be done by a qualified clinician alongside the full clinical picture.
Common Anion Gap Mistakes to Avoid
- Interpreting an anion gap value in isolation without clinical context — this is a lab calculation meant to support diagnosis, not a standalone diagnostic answer.
When to Use This Calculator
The anion gap is a calculated value used in clinical medicine to help identify and classify the cause of metabolic acidosis, based on routine electrolyte panel results.