diff --git a/renderdoc/driver/gl/gl_manager.cpp b/renderdoc/driver/gl/gl_manager.cpp
index ace951ebe..a2ed1590c 100644
--- a/renderdoc/driver/gl/gl_manager.cpp
+++ b/renderdoc/driver/gl/gl_manager.cpp
@@ -837,7 +837,7 @@ void GLResourceManager::PrepareTextureInitialContents(ResourceId liveid, Resourc
 
           for(int trg = 0; trg < count; trg++)
           {
-            size_t size = GetCompressedByteSize(w, h, d, details.internalFormat, i);
+            size_t size = GetCompressedByteSize(w, h, d, details.internalFormat);
 
             byte *buf = new byte[size];
 
@@ -1150,7 +1150,7 @@ bool GLResourceManager::Serialise_InitialState(ResourceId resid, GLResource res)
 
             for(int trg = 0; trg < count; trg++)
             {
-              size_t size = GetCompressedByteSize(w, h, d, details.internalFormat, i);
+              size_t size = GetCompressedByteSize(w, h, d, details.internalFormat);
 
               byte *buf = new byte[size];
 
@@ -1317,7 +1317,7 @@ bool GLResourceManager::Serialise_InitialState(ResourceId resid, GLResource res)
               {
                 if(isCompressed)
                 {
-                  GLsizei compSize = (GLsizei)GetCompressedByteSize(w, h, d, internalformat, m);
+                  GLsizei compSize = (GLsizei)GetCompressedByteSize(w, h, d, internalformat);
 
                   vector<byte> dummy;
                   dummy.resize(compSize);
@@ -1786,7 +1786,7 @@ void GLResourceManager::Apply_InitialState(GLResource live, InitialContentData i
 
             for(int trg = 0; trg < count; trg++)
             {
-              size_t size = GetCompressedByteSize(w, h, d, details.internalFormat, i);
+              size_t size = GetCompressedByteSize(w, h, d, details.internalFormat);
 
               if(details.curType == eGL_TEXTURE_CUBE_MAP)
                 size /= 6;
diff --git a/renderdoc/driver/gl/gl_replay.cpp b/renderdoc/driver/gl/gl_replay.cpp
index 9df9385aa..826392681 100644
--- a/renderdoc/driver/gl/gl_replay.cpp
+++ b/renderdoc/driver/gl/gl_replay.cpp
@@ -712,9 +712,8 @@ void GLReplay::CacheTexture(ResourceId id)
     {
       if(compressed)
       {
-        gl.glGetTextureLevelParameterivEXT(res.resource.name, levelQueryType, m,
-                                           eGL_TEXTURE_COMPRESSED_IMAGE_SIZE, &compressed);
-        tex.byteSize += compressed;
+        tex.byteSize += (uint64_t)GetCompressedByteSize(
+            RDCMAX(1U, tex.width >> m), RDCMAX(1U, tex.height >> m), 1, (GLenum)fmt);
       }
       else if(tex.format.special)
       {
diff --git a/renderdoc/driver/gl/gl_resources.cpp b/renderdoc/driver/gl/gl_resources.cpp
index 6a7a4426f..e57310c69 100644
--- a/renderdoc/driver/gl/gl_resources.cpp
+++ b/renderdoc/driver/gl/gl_resources.cpp
@@ -30,7 +30,7 @@ byte GLResourceRecord::markerValue[32] = {
     0xaa, 0xbb, 0xcc, 0xdd, 0x88, 0x77, 0x66, 0x55, 0x01, 0x23, 0x45, 0x67, 0x98, 0x76, 0x54, 0x32,
 };
 
-size_t GetCompressedByteSize(GLsizei w, GLsizei h, GLsizei d, GLenum internalformat, int mip)
+size_t GetCompressedByteSize(GLsizei w, GLsizei h, GLsizei d, GLenum internalformat)
 {
   if(!IsCompressedFormat(internalformat))
   {
diff --git a/renderdoc/driver/gl/gl_resources.h b/renderdoc/driver/gl/gl_resources.h
index 5a826636e..383567166 100644
--- a/renderdoc/driver/gl/gl_resources.h
+++ b/renderdoc/driver/gl/gl_resources.h
@@ -30,7 +30,7 @@
 
 struct GLHookSet;
 
-size_t GetCompressedByteSize(GLsizei w, GLsizei h, GLsizei d, GLenum internalformat, int mip);
+size_t GetCompressedByteSize(GLsizei w, GLsizei h, GLsizei d, GLenum internalformat);
 size_t GetByteSize(GLsizei w, GLsizei h, GLsizei d, GLenum format, GLenum type);
 GLenum GetBaseFormat(GLenum internalFormat);
 GLenum GetDataType(GLenum internalFormat);
diff --git a/renderdoc/driver/gl/wrappers/gl_emulated.cpp b/renderdoc/driver/gl/wrappers/gl_emulated.cpp
index d12b661cf..fe3e31b47 100644
--- a/renderdoc/driver/gl/wrappers/gl_emulated.cpp
+++ b/renderdoc/driver/gl/wrappers/gl_emulated.cpp
@@ -1109,7 +1109,7 @@ void APIENTRY _glCopyImageSubData(GLuint srcName, GLenum srcTarget, GLint srcLev
           count = 1;
         }
 
-        size_t size = GetCompressedByteSize(srcWidth, srcHeight, srcDepth, fmt, srcLevel);
+        size_t size = GetCompressedByteSize(srcWidth, srcHeight, srcDepth, fmt);
 
         if(srcTarget == eGL_TEXTURE_CUBE_MAP)
           size /= 6;