Net GEX (Net Gamma Exposure): What It Measures and How to Read the Chart

Before this article: 0DTE Options: Why Same-Day Expiration Gamma Hits Different.

From formula to chart

In the previous articles you built, piece by piece, everything: Delta, Gamma, the aggregate per-strike hedging formula. Net GEX is where all of that turns into the chart you'll actually look at every day.

The formula, per strike

GEX at a strike, for calls and puts separately:

$$ GEX_k = \Gamma_k \times OI_k \times M $$

Where:

$GEX_k$ = Gamma Exposure at strike $k$.
$\Gamma_k$ = Gamma of the option at that strike.
$OI_k$ = open interest at that strike.
$M$ = the contract multiplier.

Net GEX at that strike is the difference between call GEX and put GEX:

$$ \text{Net GEX}_k = GEX_k^{\text{call}} - GEX_k^{\text{put}} $$

And total market Net GEX is the sum across every strike:

$$ \text{Net GEX} = \sum_k \text{Net GEX}_k $$

Key idea: a strike dominated by calls contributes positively to the total. A strike dominated by puts contributes negatively. The bar chart you see on the dashboard is, literally, this formula applied strike by strike.

flowchart TB
    A[Call GEX at strike k] --> C[Net GEX at strike k]
    B[Put GEX at strike k] --> C
    C --> D[Sum across every strike]
    D --> E[Total market Net GEX]

How to read the chart

Chart element	What it means
Positive bar at a strike	Call dominance at that strike: a zone where hedging tends to sell as price approaches
Negative bar at a strike	Put dominance at that strike: a zone where hedging tends to buy as price approaches
Larger bars	Higher Gamma Exposure concentration: candidates for structural levels (Call Wall / Put Wall, covered in a dedicated article)
The point where total Net GEX crosses from positive to negative	The Gamma Flip: the boundary between the Long Gamma Regime and the Short Gamma Regime

Numeric example

Example: at a strike on the underlying with 0.015 Gamma and 20,000 open call contracts ($M = 100$):

$$GEX^{\text{call}} = 0.015 \times 20{,}000 \times 100 = 30{,}000$$

At that same strike there are 5,000 put contracts with 0.010 Gamma:

$$GEX^{\text{put}} = 0.010 \times 5{,}000 \times 100 = 5{,}000$$

Net GEX at that strike:

$$\text{Net GEX}_k = 30{,}000 - 5{,}000 = 25{,}000 \text{ (positive)}$$

That strike pushes the market toward the Long Gamma Regime. Illustrative figures to show the calculation.

Net GEX bar chart by strike

Next step

You now know exactly what the chart measures and how it's built. The next article in this guide covers the most important level read directly from this chart: the Gamma Flip, the point where the regime changes.

Continue with: Gamma Flip: The Level Where the Market's Regime Changes (/docs/gamma-flip-explained, next wave)