diff --git a/vskernels/kernels/bicubic.py b/vskernels/kernels/bicubic.py
index d2d8850..555a9c5 100644
--- a/vskernels/kernels/bicubic.py
+++ b/vskernels/kernels/bicubic.py
@@ -3,6 +3,7 @@
 from math import acos, asinh, cos, sqrt
 from typing import TYPE_CHECKING, Any
 
+from stgpytools import classproperty
 from vstools import CustomValueError, core, vs
 
 from .complex import ComplexKernel
@@ -68,7 +69,7 @@ def get_params_args(
             return args | dict(b=self.b, c=self.c)
         return args | dict(filter_param_a=self.b, filter_param_b=self.c)
 
-    @property
+    @classproperty
     def kernel_size(self) -> int:
         return 1 + ((self.b, self.c) != (0, 0))
 
diff --git a/vskernels/kernels/placebo.py b/vskernels/kernels/placebo.py
index b505014..0afe2c6 100644
--- a/vskernels/kernels/placebo.py
+++ b/vskernels/kernels/placebo.py
@@ -3,6 +3,7 @@
 from math import ceil
 from typing import TYPE_CHECKING, Any
 
+from stgpytools import classproperty
 from vstools import Transfer, TransferT, core, fallback, inject_self, vs
 
 from .complex import LinearScaler
@@ -93,6 +94,6 @@ def _kernel_size(self, taps: float | None = None, b: float | None = None, c: flo
 
         return 1
 
-    @property
+    @classproperty
     def kernel_size(self) -> int:
         return self._kernel_size(self.taps, self.b, self.c)
diff --git a/vskernels/kernels/resize.py b/vskernels/kernels/resize.py
index f36b97d..4bddc59 100644
--- a/vskernels/kernels/resize.py
+++ b/vskernels/kernels/resize.py
@@ -3,6 +3,7 @@
 from math import ceil
 from typing import Any
 
+from stgpytools import classproperty
 from vstools import core, vs
 
 from .zimg import ZimgComplexKernel
@@ -26,7 +27,7 @@ class Bilinear(ZimgComplexKernel):
     scale_function = resample_function = core.lazy.resize.Bilinear
     descale_function = core.lazy.descale.Debilinear
 
-    @property
+    @classproperty
     def kernel_size(self) -> int:
         return 1
 
@@ -57,6 +58,6 @@ def get_params_args(
             return args | dict(taps=self.taps)
         return args | dict(filter_param_a=self.taps)
 
-    @property
+    @classproperty
     def kernel_size(self) -> int:
         return ceil(self.taps)
diff --git a/vskernels/kernels/spline.py b/vskernels/kernels/spline.py
index 52b6ea9..bff41d4 100644
--- a/vskernels/kernels/spline.py
+++ b/vskernels/kernels/spline.py
@@ -4,6 +4,7 @@
 from math import ceil, isqrt
 from typing import Any
 
+from stgpytools import classproperty
 from vstools import core
 
 from .zimg import ZimgComplexKernel
@@ -20,7 +21,7 @@
 class _SplineKernelSize:
     """Spline kernel size sub-class."""
 
-    @property
+    @classproperty
     def kernel_size(self) -> int:
         radius = re.search(r'\d+$', self.__class__.__name__)
 
@@ -38,7 +39,7 @@ class Spline(FmtConv):
     def __init__(self, taps: int = 2, **kwargs: Any) -> None:
         super().__init__(taps=taps, **kwargs)
 
-    @property
+    @classproperty
     def kernel_size(self) -> int:
         return ceil(self.taps)