diff --git a/lindi/conversion/create_zarr_dataset_from_h5_data.py b/lindi/conversion/create_zarr_dataset_from_h5_data.py
index 0d0b500..6998cd6 100644
--- a/lindi/conversion/create_zarr_dataset_from_h5_data.py
+++ b/lindi/conversion/create_zarr_dataset_from_h5_data.py
@@ -266,7 +266,7 @@ def _get_default_chunks(shape: Tuple, dtype: Any) -> Tuple:
     shape_prod_0 = np.prod(shape[1:])
     optimal_chunk_size_bytes = 1024 * 1024 * 20  # 20 MB
     optimal_chunk_size = optimal_chunk_size_bytes // (dtype_size * shape_prod_0)
-    if optimal_chunk_size <= shape[0]:
+    if optimal_chunk_size > shape[0]:
         return shape
     if optimal_chunk_size < 1:
         return (1,) + shape[1:]
diff --git a/pyproject.toml b/pyproject.toml
index ff95166..66f5b10 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "lindi"
-version = "0.4.1"
+version = "0.4.2"
 description = ""
 authors = [
     "Jeremy Magland <jmagland@flatironinstitute.org>",