Motion / Time
Timecode Drift & Audio Sync Calculator
Estimate how far two unlocked devices will drift apart over a recording, in seconds and frames, based on their clock accuracy, live as you type.
Recording Duration
Device Clock Accuracy
Results
Jam-syncing timecode periodically resets accumulated drift to zero — use the re-sync interval above as a guide for how often to do it.
Why Unlocked Timecode Drifts Apart
Every camera and audio recorder keeps time with its own internal crystal oscillator, and no two crystals run at exactly the same rate. Left unjammed over a long recording, two devices’ timecode will gradually drift apart — slowly at first, but enough over hours to knock audio and picture noticeably out of sync. This tool estimates exactly how much drift to expect.
What PPM Actually Means
Clock accuracy is usually specified in parts per million (ppm) — how many microseconds of error accumulate per second of runtime. Consumer cameras often run around ±20 ppm, broadcast-grade gear closer to ±5 ppm, and GPS-locked or atomic references can hold under 1 ppm. What matters for sync isn’t either device’s absolute accuracy but the difference between the two — two devices both running fast by the same amount stay perfectly in sync with each other even if neither is technically correct.
Deciding How Often to Re-Sync
The results include an estimate of how long it takes for drift to reach a full frame at your project’s frame rate — a useful threshold, since a full frame of drift is often the point where sync starts to look or sound wrong. Use that number to decide how frequently to jam-sync timecode or clap a slate during a long shoot.
This tool is especially useful for:
- Multi-camera and dual-system sound shoots planning a re-sync schedule.
- Documentary and long-form productions recording for hours without a hard-wired timecode link.
- Post-production teams troubleshooting gradual sync drift on long takes.