diff --git a/src/datachain/toolkit/split.py b/src/datachain/toolkit/split.py
index 1fb62fe0..426c2495 100644
--- a/src/datachain/toolkit/split.py
+++ b/src/datachain/toolkit/split.py
@@ -58,10 +58,14 @@ def train_test_split(dc: DataChain, weights: list[float]) -> list[DataChain]:
 
     weights_normalized = [weight / sum(weights) for weight in weights]
 
+    resolution = 2**31 - 1  # Maximum positive value for a 32-bit signed integer.
+
     return [
         dc.filter(
-            C("sys__rand") % 1000 >= round(sum(weights_normalized[:index]) * 1000),
-            C("sys__rand") % 1000 < round(sum(weights_normalized[: index + 1]) * 1000),
+            C("sys__rand") % resolution
+            >= round(sum(weights_normalized[:index]) * resolution),
+            C("sys__rand") % resolution
+            < round(sum(weights_normalized[: index + 1]) * resolution),
         )
         for index, _ in enumerate(weights_normalized)
     ]
diff --git a/tests/conftest.py b/tests/conftest.py
index 3a15e216..1291643e 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -707,16 +707,16 @@ def studio_datasets(requests_mock):
 def not_random_ds(test_session):
     return DataChain.from_records(
         [
-            {"sys__id": 1, "sys__rand": 50, "fib": 0},
-            {"sys__id": 2, "sys__rand": 150, "fib": 1},
-            {"sys__id": 3, "sys__rand": 250, "fib": 1},
-            {"sys__id": 4, "sys__rand": 350, "fib": 2},
-            {"sys__id": 5, "sys__rand": 450, "fib": 3},
-            {"sys__id": 6, "sys__rand": 550, "fib": 5},
-            {"sys__id": 7, "sys__rand": 650, "fib": 8},
-            {"sys__id": 8, "sys__rand": 750, "fib": 13},
-            {"sys__id": 9, "sys__rand": 850, "fib": 21},
-            {"sys__id": 10, "sys__rand": 950, "fib": 34},
+            {"sys__id": 1, "sys__rand": 200000000, "fib": 0},
+            {"sys__id": 2, "sys__rand": 400000000, "fib": 1},
+            {"sys__id": 3, "sys__rand": 600000000, "fib": 1},
+            {"sys__id": 4, "sys__rand": 800000000, "fib": 2},
+            {"sys__id": 5, "sys__rand": 1000000000, "fib": 3},
+            {"sys__id": 6, "sys__rand": 1200000000, "fib": 5},
+            {"sys__id": 7, "sys__rand": 1400000000, "fib": 8},
+            {"sys__id": 8, "sys__rand": 1600000000, "fib": 13},
+            {"sys__id": 9, "sys__rand": 1800000000, "fib": 21},
+            {"sys__id": 10, "sys__rand": 2000000000, "fib": 34},
         ],
         session=test_session,
         schema={"sys": Sys, "fib": int},
@@ -727,16 +727,16 @@ def not_random_ds(test_session):
 def pseudo_random_ds(test_session):
     return DataChain.from_records(
         [
-            {"sys__id": 1, "sys__rand": 1344339883, "fib": 0},
-            {"sys__id": 2, "sys__rand": 3901153096, "fib": 1},
-            {"sys__id": 3, "sys__rand": 4255991360, "fib": 1},
-            {"sys__id": 4, "sys__rand": 2526403609, "fib": 2},
-            {"sys__id": 5, "sys__rand": 1871733386, "fib": 3},
-            {"sys__id": 6, "sys__rand": 9380910850, "fib": 5},
-            {"sys__id": 7, "sys__rand": 2770679740, "fib": 8},
-            {"sys__id": 8, "sys__rand": 2538886575, "fib": 13},
-            {"sys__id": 9, "sys__rand": 3969542617, "fib": 21},
-            {"sys__id": 10, "sys__rand": 7541790992, "fib": 34},
+            {"sys__id": 1, "sys__rand": 2406827533654413759, "fib": 0},
+            {"sys__id": 2, "sys__rand": 743035223448130834, "fib": 1},
+            {"sys__id": 3, "sys__rand": 8572034894545971037, "fib": 1},
+            {"sys__id": 4, "sys__rand": 3413911135601125438, "fib": 2},
+            {"sys__id": 5, "sys__rand": 8036488725627198326, "fib": 3},
+            {"sys__id": 6, "sys__rand": 2020789040280779494, "fib": 5},
+            {"sys__id": 7, "sys__rand": 8478782014085172114, "fib": 8},
+            {"sys__id": 8, "sys__rand": 1374262678671783922, "fib": 13},
+            {"sys__id": 9, "sys__rand": 7728884931956308771, "fib": 21},
+            {"sys__id": 10, "sys__rand": 5591681088079559562, "fib": 34},
         ],
         session=test_session,
         schema={"sys": Sys, "fib": int},
diff --git a/tests/func/test_pull.py b/tests/func/test_pull.py
index 9f7415d0..24ce20bf 100644
--- a/tests/func/test_pull.py
+++ b/tests/func/test_pull.py
@@ -78,7 +78,7 @@ def _adapt_row(row):
 def schema():
     return {
         "id": {"type": "UInt64"},
-        "sys__rand": {"type": "Int64"},
+        "sys__rand": {"type": "UInt64"},
         "file__path": {"type": "String"},
         "file__etag": {"type": "String"},
         "file__version": {"type": "String"},
diff --git a/tests/func/test_toolkit.py b/tests/func/test_toolkit.py
index f2388254..673475eb 100644
--- a/tests/func/test_toolkit.py
+++ b/tests/func/test_toolkit.py
@@ -22,9 +22,9 @@ def test_train_test_split_not_random(not_random_ds, weights, expected):
 @pytest.mark.parametrize(
     "weights,expected",
     [
-        [[1, 1], [[2, 3, 5], [1, 4, 6, 7, 8, 9, 10]]],
-        [[4, 1], [[2, 3, 4, 5, 7, 8, 9], [1, 6, 10]]],
-        [[0.7, 0.2, 0.1], [[2, 3, 4, 5, 8, 9], [1, 6, 7], [10]]],
+        [[1, 1], [[1, 5, 6, 7, 8], [2, 3, 4, 9, 10]]],
+        [[4, 1], [[1, 3, 5, 6, 7, 8, 9], [2, 4, 10]]],
+        [[0.7, 0.2, 0.1], [[1, 3, 5, 6, 7, 8, 9], [2, 4], [10]]],
     ],
 )
 def test_train_test_split_random(pseudo_random_ds, weights, expected):