diff --git a/ROADMAP.md b/ROADMAP.md
index 25ae055f..dd79f695 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -122,6 +122,7 @@ mutated and truncated movies. Field reports from the first public week are track
 
 ## Progress log
 
+- **2026-10-12:** Timecode labels with huge fields no longer overflow: frame counts are computed in 128 bits and clamp, so `setup.current_timecode` and `session.format_time` saturate instead of failing (#248)
 - **2026-10-10 (UI docking):** Tracks and Groups, Clips, MIDI Editor, Memory Locations, and Undo History use movable panels. Edit and Mix retain separate arrangements; Clips and MIDI Editor belong to Edit. Transport, plug-in, and specialist utility windows retain their existing hosts. Panel moves and reset are available as UI commands, and saved UI preferences retain arrangements. Common toolbar and track record-enable buttons share interaction, accessible labels and keyboard focus through `craft-ui`, retaining blue tool selection and red record-arm states. No readiness percentage change.
 - **2026-10-10** — Stage re-normalized to **pre-alpha** by the core-workflow gate (interface recording, MIDI recording and session interchange fail). Full re-measure against Pro Tools Ultimate 2026.4.1 and the standard
   progress-docs set (this page, target-app parity, gaps, roadmap, UI/format/hardware/plugin/
@@ -143,6 +144,7 @@ mutated and truncated movies. Field reports from the first public week are track
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-12 | trivial | Progress log: timecode overflow (#248) |
 | 2026-10-10 | minor | Readiness-by-audience table with hours: full 950–1,450 h, mainstream 380–600 h, essentials 110–200 h |
 | 2026-10-10 | minor | Added mainstream practitioner ~36 % and essentials user ~57 % to the headline numbers |
 | 2026-10-10 | minor | Stage alpha → pre-alpha: the core-workflow gate fails on interface recording, MIDI recording and session interchange; alpha distance added |
diff --git a/crates/time/src/timecode.rs b/crates/time/src/timecode.rs
index 64cba7c8..f8f6041b 100644
--- a/crates/time/src/timecode.rs
+++ b/crates/time/src/timecode.rs
@@ -109,7 +109,7 @@ impl FrameRate {
             return 0;
         }
         let v = (i128::from(f) * i128::from(sr.hz()) * i128::from(d) + i128::from(n) / 2) / i128::from(n);
-        i64::try_from(v).unwrap_or(0)
+        i64::try_from(v).unwrap_or(if v < 0 { i64::MIN } else { i64::MAX })
     }
 
     /// Samples per frame (fractional).
@@ -153,13 +153,14 @@ impl Timecode {
     /// Absolute frame count of this label.
     pub fn to_frames(&self, rate: FrameRate) -> i64 {
         let base = rate.nominal().max(1);
-        let total_min = self.hours * 60 + self.minutes;
-        let mut f = (total_min * 60 + self.seconds) * base + self.frames;
+        let total_min = i128::from(self.hours) * 60 + i128::from(self.minutes);
+        let mut f = (total_min * 60 + i128::from(self.seconds)) * i128::from(base) + i128::from(self.frames);
         if rate.is_drop() {
             let drop = if base >= 60 { 4 } else { 2 };
             f -= drop * (total_min - total_min / 10);
         }
-        if self.negative { -f } else { f }
+        let f = if self.negative { -f } else { f };
+        i64::try_from(f).unwrap_or(if f < 0 { i64::MIN } else { i64::MAX })
     }
 
     pub fn from_samples(s: Samples, rate: FrameRate, sr: SampleRate) -> Timecode {
@@ -233,6 +234,19 @@ mod tests {
         }
     }
 
+    #[test]
+    fn huge_timecode_saturates_instead_of_overflowing() {
+        let sr = SampleRate::HZ_48000;
+        for r in [FrameRate::Fps30, FrameRate::Fps29_97Drop] {
+            let tc = Timecode::parse("9223372036854775807:00:00:00").unwrap();
+            assert_eq!(tc.to_samples(r, sr), i64::MAX);
+            let tc = Timecode::parse("-9223372036854775807:00:00:00").unwrap();
+            assert_eq!(tc.to_samples(r, sr), i64::MIN);
+        }
+        let tc = Timecode::parse("01:02:03:04").unwrap();
+        assert_eq!(tc.to_samples(FrameRate::Fps30, sr), 178_710_400);
+    }
+
     #[test]
     fn parse_variants() {
         let tc = Timecode::parse("01:02:03:04").unwrap();