diff --git a/src/jax_finufft/lowering.py b/src/jax_finufft/lowering.py
index 9981e33..365973d 100644
--- a/src/jax_finufft/lowering.py
+++ b/src/jax_finufft/lowering.py
@@ -56,14 +56,14 @@ def lowering(
     n_transf = source_shape[1]
     n_j = points_shape[0][1]
 
+    # Dispatch to the correct custom call target depending on the dimension,
+    # dtype, and NUFFT type.
     if output_shape is None:  # Type 2
         op_name = f"nufft{ndim}d2{suffix}".encode("ascii")
         n_k = np.array(source_shape[2:], dtype=np.int64)
-        full_output_shape = tuple(source_shape[:2]) + (n_j,)
     else:  # Type 1
         op_name = f"nufft{ndim}d1{suffix}".encode("ascii")
         n_k = np.array(output_shape, dtype=np.int64)
-        full_output_shape = tuple(source_shape[:2]) + tuple(output_shape)
 
     # The backend expects the output shape in Fortran order, so we'll just
     # fake it here, by sending in n_k and x in the reverse order.
@@ -87,7 +87,7 @@ def lowering(
             # Reverse points because backend uses Fortran order
             operands=[descriptor, source, *points[::-1]],
             operand_layouts=default_layouts([0], source_shape, *points_shape[::-1]),
-            result_layouts=default_layouts(full_output_shape),
+            result_layouts=default_layouts(ctx.avals_out[0].shape),
         ).results
 
     else:
@@ -102,5 +102,5 @@ def lowering(
             operands=[source, *points[::-1]],
             backend_config=descriptor_bytes,
             operand_layouts=default_layouts(source_shape, *points_shape[::-1]),
-            result_layouts=default_layouts(full_output_shape),
+            result_layouts=default_layouts(ctx.avals_out[0].shape),
         ).results