diff --git a/pyproject.toml b/pyproject.toml
index 492a88a3c1..15b8391cdb 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -95,7 +95,6 @@ module = [
     "pytorch_lightning.utilities.auto_restart",
     "pytorch_lightning.utilities.data",
     "pytorch_lightning.utilities.distributed",
-    "pytorch_lightning.utilities.memory",
     "pytorch_lightning.utilities.meta",
 ]
 ignore_errors = "True"
diff --git a/pytorch_lightning/utilities/memory.py b/pytorch_lightning/utilities/memory.py
index e945083217..dec00412ba 100644
--- a/pytorch_lightning/utilities/memory.py
+++ b/pytorch_lightning/utilities/memory.py
@@ -17,6 +17,7 @@ import gc
 import os
 import shutil
 import subprocess
+from io import BytesIO
 from typing import Any, Dict
 
 import torch
@@ -25,20 +26,6 @@ from torch.nn import Module
 from pytorch_lightning.utilities.apply_func import apply_to_collection
 
 
-class _ByteCounter:
-    """Accumulate and stores the total bytes of an object."""
-
-    def __init__(self) -> None:
-        self.nbytes: int = 0
-
-    def write(self, data: bytes) -> None:
-        """Stores the total bytes of the data."""
-        self.nbytes += len(data)
-
-    def flush(self) -> None:
-        pass
-
-
 def recursive_detach(in_dict: Any, to_cpu: bool = False) -> Any:
     """Detach all tensors in `in_dict`.
 
@@ -183,7 +170,7 @@ def get_model_size_mb(model: Module) -> float:
     Returns:
         Number of megabytes in the parameters of the input module.
     """
-    model_size = _ByteCounter()
+    model_size = BytesIO()
     torch.save(model.state_dict(), model_size)
-    size_mb = model_size.nbytes / 1e6
+    size_mb = model_size.getbuffer().nbytes / 1e6
     return size_mb