Why does Unity say the shader keyword limit is exceeded?

Unity has a hard limit (256 in modern versions, 384+ recently) on global shader keywords. Custom keywords from your shaders plus those from URP/HDRP can exceed it. Use multi_compile_local instead of multi_compile to keep keywords local to one shader, and avoid declaring keywords you do not use.

What is the difference between multi_compile and multi_compile_local?

multi_compile keywords are global; declaring a keyword in one shader counts against the global budget for everyone. multi_compile_local keeps the keyword scoped to that shader, not consuming global slots. Prefer local unless you need cross-shader keyword control via Shader.EnableKeyword.

How do I list current shader keywords in use?

In code, Shader.globalKeywords lists currently enabled global keywords. For all declared keywords, the Shader.GetKeywordCount() and the Editor's Shader window let you inspect declared variants. Strip unused keywords from your shaders to free budget.

Fix: Unity Shader Keyword Limit Exceeded Error

Quick answer: Switch multi_compile to multi_compile_local in your shaders so keywords do not consume the global budget. Audit URP/HDRP unused features and disable them to free slots. Use shader_feature_local when keywords are material-driven rather than runtime-toggled.

Here is how to fix Unity emitting Maximum number of shader keywords exceeded errors when you add another shader feature. The error appears in the console; some materials render incorrectly. Each project shares a global keyword budget; once exhausted, new keywords get dropped silently or emit errors.

The Symptom

Console error: Maximum number of shader keywords exceeded! Keyword 'X' is dropped. Shaders that depend on the dropped keyword render with the wrong variant. Often appears after adding a new third-party shader pack.

What Causes This

Too many global keywords. Unity caps global keyword count (256 historically, raised to 384+ in recent versions). Custom shaders + URP/HDRP defaults can blow past it.

multi_compile instead of local. multi_compile declares global keywords. multi_compile_local declares per-shader, not consuming global budget.

Forgotten keywords. Unused keywords still count. Cleaning shader source removes them.

The Fix

Step 1: Convert multi_compile to local.

// Before
#pragma multi_compile _WIND_ON _WIND_OFF

// After
#pragma multi_compile_local _WIND_ON _WIND_OFF

Local keywords stay scoped to this shader. Material code still toggles them via material.EnableKeyword.

Step 2: Use shader_feature for material-time choices.

// Compile-time choice baked into material asset
#pragma shader_feature_local _NORMALMAP _NORMALMAP_OFF

shader_feature variants are only included if at least one material uses them, saving build size and runtime budget.

Step 3: Audit URP/HDRP features. Open the URP/HDRP Asset and disable unused features (additional lights, baked shadows for unused light types, post-processing volumes you do not use). Each feature contributes keywords.

Step 4: Inspect declared keywords.

using UnityEngine.Rendering;

void ListGlobalKeywords()
{
    foreach (var kw in Shader.globalKeywords)
        Debug.Log(kw.name);
    Debug.Log($"Total enabled: {Shader.globalKeywords.Length}");
}

Helps identify a chatty subsystem.

Step 5: Remove unused keywords from third-party shaders. If a shader pack declares _GLITCH_MODE, _RAINBOW, etc. you never use, edit the shader to drop the multi_compile lines. Or fork a stripped version.

Project-wide Keyword Budget

Unity 2023+ raised the budget to 384 globals plus 65k locals. If you still hit limits, your project has substantial shader feature usage; the only fix is reducing total declared keywords through audits and stripping.

“_local everything you can. shader_feature for material choices. Audit URP/HDRP. Free the global slots.”

Related Issues

For shader stripping in builds, see AssetBundle Shader Stripped. For variant collection, see Shader Variant Collection.

_local keywords. shader_feature for materials. Audit URP. Errors stop.