Aviation Training Experts

Aviation Training Experts™

%MAC Calculator

Convert center of gravity location to percent mean aerodynamic chord and convert percent MAC back to CG location. This free aviation calculator helps with aircraft design study, stability analysis, and advanced weight and balance work.

Calculate %MAC or CG Location

Use either method below. You can convert a center of gravity location into percent MAC or convert percent MAC into a CG location.

Important: This calculator is a training and planning aid. Always verify aircraft-specific station references, MAC data, and approved loading information when accuracy is critical.

Convert CG to %MAC

Convert %MAC to CG

How It Works

CG to %MAC:
%MAC = ((CG − LEMAC) ÷ MAC) × 100
%MAC to CG:
CG = LEMAC + (%MAC ÷ 100 × MAC)
Reference Terms:
LEMAC = Leading Edge of Mean Aerodynamic Chord
MAC = Mean Aerodynamic Chord

This calculator is especially useful when center of gravity is expressed as a percentage of MAC rather than as a direct station location.

What Is %MAC?

Percent MAC expresses center of gravity position as a percentage of the mean aerodynamic chord. Instead of describing CG only as a station number, %MAC shows where the CG falls along the aerodynamic reference chord.

This is commonly used in transport-category aircraft, aircraft design, certification work, and advanced weight and balance discussions because it creates a standard way to compare CG position.

Why Pilots and Students Use a %MAC Calculator

%MAC Calculator FAQ

What is LEMAC?

LEMAC is the leading edge of the mean aerodynamic chord. It is a reference location used when expressing center of gravity as a percentage of MAC.

Why use %MAC instead of a station number?

Percent MAC gives a normalized way to describe CG location, which is especially helpful for aircraft design and comparing loading positions.

Can %MAC be negative or over 100?

Mathematically yes, depending on the numbers entered. In practical aircraft loading, acceptable values depend on the aircraft’s approved CG range.

Does this calculator determine if the aircraft is within CG limits?

No. It converts between station and %MAC, but you must compare the result against approved aircraft-specific CG limits.