diff --git a/CMakeLists.txt b/CMakeLists.txt
index c2e1a70c66..4ad8fbb1bf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -192,6 +192,9 @@ if(BUILD_TESTING)
             ${CMAKE_CURRENT_SOURCE_DIR}/tools/tests/test_pr_overlap.py)
         add_test(NAME pr_labels COMMAND ${Python3_EXECUTABLE}
             ${CMAKE_CURRENT_SOURCE_DIR}/tools/tests/test_pr_labels.py)
+        add_test(NAME progress_history_date_window COMMAND ${Python3_EXECUTABLE}
+            ${CMAKE_CURRENT_SOURCE_DIR}/tools/tests/test_progress_history.py HistoryDateWindowTests)
+        set_tests_properties(progress_history_date_window PROPERTIES TIMEOUT 20)
         add_test(NAME progress_history COMMAND ${Python3_EXECUTABLE}
             ${CMAKE_CURRENT_SOURCE_DIR}/tools/tests/test_progress_history.py ProgressHistoryTests)
         add_test(NAME progress_history_output COMMAND ${Python3_EXECUTABLE}
diff --git a/tools/progress_history.py b/tools/progress_history.py
index 67deef9d1b..bdfaba3e43 100644
--- a/tools/progress_history.py
+++ b/tools/progress_history.py
@@ -113,11 +113,22 @@ def save_cache(path, signature, commits):
             temporary.unlink(missing_ok=True)
 
 
-def collect(ref, cache=None):
+def utc_day(value):
+    try:
+        if date.fromisoformat(value).isoformat() == value:
+            return value
+    except ValueError:
+        pass
+    raise argparse.ArgumentTypeError("date bounds must be valid YYYY-MM-DD UTC days")
+
+
+def collect(ref, cache=None, since=None, until=None):
     signature = cache_signature() if cache is not None else None
     records = load_cache(cache, signature) if cache is not None else {}
     points, changed = [], False
     for day, sha in daily_commits(ref):
+        if (since is not None and day < since) or (until is not None and day > until):
+            continue
         if sha not in records:
             records[sha] = measure(sha)
             changed = True
@@ -228,6 +239,8 @@ def page(points):
 
 def main(argv=None):
     parser = argparse.ArgumentParser()
+    parser.add_argument("--since", type=utc_day, help="first UTC day to measure, inclusive (YYYY-MM-DD)")
+    parser.add_argument("--until", type=utc_day, help="last UTC day to measure, inclusive (YYYY-MM-DD)")
     parser.add_argument("output", type=Path)
     parser.add_argument("--ref", default="HEAD", help="branch or commit whose first-parent history is measured")
     parser.add_argument("--cache", type=Path, help="reuse per-commit counts while the scanner, ISA list and Python version match")
@@ -242,7 +255,9 @@ def main(argv=None):
             if any(args.cache.resolve() == path.resolve() or
                    (args.cache.exists() and path.exists() and args.cache.samefile(path)) for path in outputs):
                 raise ValueError("history cache must differ from generated reports")
-        points = collect(args.ref, args.cache)
+        if args.since and args.until and args.since > args.until:
+            raise ValueError("--since must not be later than --until")
+        points = collect(args.ref, args.cache, args.since, args.until)
     except (OSError, ValueError) as error:
         parser.error(str(error))
     if not points:
diff --git a/tools/tests/test_progress_history.py b/tools/tests/test_progress_history.py
index 507be5ff7e..1a61f401c7 100644
--- a/tools/tests/test_progress_history.py
+++ b/tools/tests/test_progress_history.py
@@ -67,6 +67,34 @@ class HistoryReportOutputTests(unittest.TestCase):
                             self.assertGreater((output / filename).stat().st_size, 0)
 
 
+class HistoryDateWindowTests(unittest.TestCase):
+    def test_window_filters_days_before_measurement_and_reuses_cache(self):
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            subprocess.run(["git", "init", "-q", directory], check=True)
+            for day, time, name in (("2026-01-01", "23:59:59Z", "A"), ("2026-01-02", "00:00:00Z", "B"), ("2026-01-02", "23:59:59Z", "C"), ("2026-01-03", "00:00:00Z", "D")):
+                commit(root, day, name, f"int APS5_VABI {name}() {{ return 0; }}\n", time)
+            with patch.multiple(progress, ROOT=root, PRX=root / "core/libs/prx", OPCODES=root / OPCODES):
+                all_days = progress_history.daily_commits("HEAD")
+                expected = [all_days[1][1]]
+                actual_measure = progress_history.measure
+                with patch.object(progress_history, "measure", wraps=actual_measure) as measure:
+                    selected = progress_history.collect("HEAD", root / "cache", "2026-01-02", "2026-01-02")
+                    self.assertEqual([c.args[0] for c in measure.call_args_list], expected)
+                self.assertEqual([p["date"] for p in selected], ["2026-01-02"])
+                with patch.object(progress_history, "measure", side_effect=AssertionError("cache missed")):
+                    self.assertEqual(progress_history.collect("HEAD", root / "cache", "2026-01-02", "2026-01-02"), selected)
+                self.assertEqual(len(progress_history.collect("HEAD", root / "cache")), 3)
+                self.assertEqual(progress_history.collect("HEAD", since="2027-01-01"), [])
+
+    def test_invalid_cli_bounds(self):
+        for options in (("--since", "20260201"), ("--until", "2026-02-30"), ("--since", "2026-02-02", "--until", "2026-02-01")):
+            with self.subTest(options=options), contextlib.redirect_stderr(io.StringIO()), self.assertRaises(SystemExit) as error:
+                progress_history.main(["unused-output", *options])
+            self.assertEqual(error.exception.code, 2)
+
+
+
 class ProgressHistoryTests(unittest.TestCase):
     @unittest.skipUnless(os.name == "nt", "requires Windows read-only replacement semantics")
     def test_readonly_cache_failure_cleans_temporary_and_can_retry(self):