diff --git a/sgkit/tests/io/vcf/test_vcf_benchmark.py b/sgkit/tests/io/vcf/test_vcf_benchmark.py
new file mode 100644
index 000000000..1b8571a3b
--- /dev/null
+++ b/sgkit/tests/io/vcf/test_vcf_benchmark.py
@@ -0,0 +1,84 @@
+import gzip
+import os
+import shutil
+import time
+
+from sgkit.io.vcf.vcf_reader import vcf_to_zarr
+from sgkit.io.vcf.vcf_writer import zarr_to_vcf
+from sgkit.tests.io.vcf.utils import path_for_test
+
+
+def test_vcf_read_speed(shared_datadir, tmp_path):
+    path = path_for_test(
+        shared_datadir,
+        "1000G.phase3.broad.withGenotypes.chr20.10100000.vcf.gz",
+    )
+    input_vcf = tmp_path.joinpath("1000G.vcf").as_posix()
+    output_zarr = tmp_path.joinpath("1000G.zarr").as_posix()
+
+    field_defs = {
+        "FORMAT/AD": {"Number": "R"},
+    }
+
+    gunzip(path, input_vcf)
+
+    duration = time_func(
+        vcf_to_zarr,
+        input_vcf,
+        output_zarr,
+        fields=["INFO/*", "FORMAT/*"],
+        field_defs=field_defs,
+        chunk_length=1_000,
+        target_part_size=None,
+    )
+
+    bytes_read = os.path.getsize(input_vcf)
+    speed = bytes_read / (1_000_000 * duration)
+
+    print(f"bytes read: {bytes_read}")
+    print(f"duration: {duration:.2f} s")
+    print(f"speed: {speed:.1f} MB/s")
+
+
+def test_vcf_write_speed(shared_datadir, tmp_path):
+    path = path_for_test(
+        shared_datadir,
+        "1000G.phase3.broad.withGenotypes.chr20.10100000.vcf.gz",
+    )
+    output_zarr = tmp_path.joinpath("1000G.zarr").as_posix()
+    output_vcf = tmp_path.joinpath("1000G.vcf").as_posix()
+
+    field_defs = {
+        "FORMAT/AD": {"Number": "R"},
+    }
+    vcf_to_zarr(
+        path,
+        output_zarr,
+        fields=["INFO/*", "FORMAT/*"],
+        field_defs=field_defs,
+        chunk_length=1_000,
+    )
+
+    # throw away first run due to numba jit compilation
+    for _ in range(2):
+        duration = time_func(zarr_to_vcf, output_zarr, output_vcf)
+
+    bytes_written = os.path.getsize(output_vcf)
+    speed = bytes_written / (1_000_000 * duration)
+
+    print(f"bytes written: {bytes_written}")
+    print(f"duration: {duration:.2f} s")
+    print(f"speed: {speed:.1f} MB/s")
+
+
+def time_func(func, *args, **kwargs):
+    start = time.time()
+    func(*args, **kwargs)
+    end = time.time()
+    return end - start
+
+
+def gunzip(input, output):
+    with gzip.open(input, "rb") as f_in:
+        with open(output, "wb") as f_out:
+            shutil.copyfileobj(f_in, f_out)