What is MAC in anesthesia?

MAC (Minimum Alveolar Concentration) is the concentration of an inhaled anesthetic at 1 atmosphere that prevents movement in 50% of subjects in response to a standardized surgical skin incision. It is a measure of anesthetic potency — the lower the MAC, the more potent the agent.

How does age affect this estimate?

The calculator uses the published relationship MACage = MAC40 × 10^[-0.00269(age−40)] for ages at least one year. This is exponential, not a flat subtraction of 6% per decade.

Does one MAC mean the patient is unconscious?

No. MAC is based on movement after a noxious stimulus, not awareness, memory or adequate anesthesia for an individual. The tool intentionally does not generate MAC-awake or treatment targets.

What factors increase or decrease MAC?

MAC is increased by hyperthermia, chronic alcohol use, and young age. MAC is decreased by hypothermia, opioids, benzodiazepines, age, pregnancy, hypotension, and acute alcohol intoxication.

Is this tool a substitute for clinical judgment?

No. This tool is an educational reference only. Clinical anesthetic management must be individualized and supervised by a qualified anesthesia provider. MAC values are population averages and do not account for all patient-specific factors.

MAC Anesthetic Helper

Estimate an age-adjusted population MAC reference using MACage = MAC40 × 10^[-0.00269(age−40)]. Not a dosing or depth-of-anesthesia target.

Age-Adjusted MAC Calculator

Anesthetic Agent

Patient Age (years)

Validated calculator range: 1–100 years

Inhaled Anesthetic MAC Reference

Agent	MAC (adult)	Boiling Point (°C)	Notes

Educational population estimate only. Do not use this output to select or change anesthetic concentration. MAC does not measure awareness, memory, analgesia, hemodynamic tolerance, or adequacy of anesthesia for an individual. Administration requires a qualified anesthesia professional and appropriate monitoring/resuscitation facilities.

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Summary

Estimate an age-adjusted population MAC reference using MACage = MAC40 × 10^[-0.00269(age−40)]. Not a dosing or depth-of-anesthesia target.

How it works

Select an inhaled anesthetic agent from the list or view all agents in the comparison table.
Enter the patient age to calculate the age-adjusted MAC.
The tool applies MACage = MAC40 × 10^[-0.00269(age − 40)] for ages 1–100 years.
Review the exact multiplier and formula substitution.
Treat the output only as an educational population reference, never a dosing target.

Use cases

Teaching tool for anesthesia residents and students.
Comparing potency of different volatile anesthetic agents.
Reproducing an age-adjusted MAC formula for coursework.

Frequently Asked Questions

Last updated: 2026-09-19 · Reviewed by Nham Vu