diff --git a/src/borg/helpers/parseformat.py b/src/borg/helpers/parseformat.py
index 85dc01789..e9a2c32b8 100644
--- a/src/borg/helpers/parseformat.py
+++ b/src/borg/helpers/parseformat.py
@@ -137,7 +137,7 @@ def ChunkerParams(s):
     params = s.strip().split(",")
     count = len(params)
     if count == 0:
-        raise ValueError("no chunker params given")
+        raise argparse.ArgumentTypeError("no chunker params given")
     algo = params[0].lower()
     if algo == CH_FAIL and count == 3:
         block_size = int(params[1])
@@ -152,9 +152,11 @@ def ChunkerParams(s):
             # or in-memory chunk management.
             # choose the block (chunk) size wisely: if you have a lot of data and you cut
             # it into very small chunks, you are asking for trouble!
-            raise ValueError("block_size must not be less than 64 Bytes")
+            raise argparse.ArgumentTypeError("block_size must not be less than 64 Bytes")
         if block_size > MAX_DATA_SIZE or header_size > MAX_DATA_SIZE:
-            raise ValueError("block_size and header_size must not exceed MAX_DATA_SIZE [%d]" % MAX_DATA_SIZE)
+            raise argparse.ArgumentTypeError(
+                "block_size and header_size must not exceed MAX_DATA_SIZE [%d]" % MAX_DATA_SIZE
+            )
         return algo, block_size, header_size
     if algo == "default" and count == 1:  # default
         return CHUNKER_PARAMS
@@ -162,14 +164,18 @@ def ChunkerParams(s):
     if algo == CH_BUZHASH and count == 5 or count == 4:  # [buzhash, ]chunk_min, chunk_max, chunk_mask, window_size
         chunk_min, chunk_max, chunk_mask, window_size = (int(p) for p in params[count - 4 :])
         if not (chunk_min <= chunk_mask <= chunk_max):
-            raise ValueError("required: chunk_min <= chunk_mask <= chunk_max")
+            raise argparse.ArgumentTypeError("required: chunk_min <= chunk_mask <= chunk_max")
         if chunk_min < 6:
             # see comment in 'fixed' algo check
-            raise ValueError("min. chunk size exponent must not be less than 6 (2^6 = 64B min. chunk size)")
+            raise argparse.ArgumentTypeError(
+                "min. chunk size exponent must not be less than 6 (2^6 = 64B min. chunk size)"
+            )
         if chunk_max > 23:
-            raise ValueError("max. chunk size exponent must not be more than 23 (2^23 = 8MiB max. chunk size)")
+            raise argparse.ArgumentTypeError(
+                "max. chunk size exponent must not be more than 23 (2^23 = 8MiB max. chunk size)"
+            )
         return CH_BUZHASH, chunk_min, chunk_max, chunk_mask, window_size
-    raise ValueError("invalid chunker params")
+    raise argparse.ArgumentTypeError("invalid chunker params")
 
 
 def FilesCacheMode(s):
diff --git a/src/borg/testsuite/helpers.py b/src/borg/testsuite/helpers.py
index df9b2ea2d..bfb4f5c32 100644
--- a/src/borg/testsuite/helpers.py
+++ b/src/borg/testsuite/helpers.py
@@ -368,19 +368,19 @@ def test_chunkerparams():
     assert ChunkerParams("fixed,4096") == ("fixed", 4096, 0)
     assert ChunkerParams("fixed,4096,200") == ("fixed", 4096, 200)
     # invalid values checking
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams("crap,1,2,3,4")  # invalid algo
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams("buzhash,5,7,6,4095")  # too small min. size
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams("buzhash,19,24,21,4095")  # too big max. size
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams("buzhash,23,19,21,4095")  # violates min <= mask <= max
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams("fixed,63")  # too small block size
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams("fixed,%d,%d" % (MAX_DATA_SIZE + 1, 4096))  # too big block size
-    with pytest.raises(ValueError):
+    with pytest.raises(ArgumentTypeError):
         ChunkerParams("fixed,%d,%d" % (4096, MAX_DATA_SIZE + 1))  # too big header size