diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2deeb33..140f457 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -49,11 +49,15 @@ endif()
 # CUDA architectures: cover Pascal to Blackwell for distributed binaries.
 # Pascal (61-real) is SASS-only, no virtual/PTX entry: it's the oldest
 # supported card and doesn't need to seed forward JIT compat for anything
-# older, unlike the 75-virtual baseline which does that for 7.5+.
+# older, unlike the 75-virtual baseline which does that for 7.5+. CUDA 13
+# removed offline compilation for pre-Turing architectures, so 61-real is
+# only emitted on 12.x toolkits; Blackwell (120a/121a) needs 12.8+.
 # Users can override with -DCMAKE_CUDA_ARCHITECTURES=native for local builds.
 if(NOT DEFINED CMAKE_CUDA_ARCHITECTURES)
     find_package(CUDAToolkit QUIET)
-    if(CUDAToolkit_FOUND AND CUDAToolkit_VERSION VERSION_GREATER_EQUAL "12.8")
+    if(CUDAToolkit_FOUND AND CUDAToolkit_VERSION VERSION_GREATER_EQUAL "13.0")
+        set(CMAKE_CUDA_ARCHITECTURES "75-virtual;80-virtual;86-real;89-real;120a-real;121a-real")
+    elseif(CUDAToolkit_FOUND AND CUDAToolkit_VERSION VERSION_GREATER_EQUAL "12.8")
         set(CMAKE_CUDA_ARCHITECTURES "61-real;75-virtual;80-virtual;86-real;89-real;120a-real;121a-real")
     else()
         set(CMAKE_CUDA_ARCHITECTURES "61-real;75-virtual;80-virtual;86-real;89-real")