Built for the numbers between edits
Frame Ledger is an independent tool site made by a small team. We build focused browser tools for people who need a useful answer without uploading a file or opening an account.
How the arithmetic is checked
The tools convert each timecode to an integer frame position first. Addition, subtraction and durations use those integers. Seconds use exact frame rates: 24,000/1,001, 30,000/1,001 or 60,000/1,001 for the fractional-rate families.
Our automated checks include hand-worked examples and every minute boundary across a 24-hour cycle for both drop-frame modes. The check at 29.97 DF is 00:10:00;00 = 30 × 600 − 2 × 9 = 17,982 frames. One hour is 108,000 − 108 = 107,892 frames. We also test missing labels, negative durations, midnight crossings and frame-rate rounding.
The public explanation by David Heidelberger documents the same drop-frame convention. SMPTE publishes the timecode standards. This site is independent and is not affiliated with either source.
What the tools do not know
We cannot inspect your footage or determine your project settings. A frame-rate label must match the source. Changing timecode numbers does not convert video, stretch audio, or guarantee a delivery specification. Verify results in the editing system used for your work.
Contact the team
Questions or a reproducible calculation error: [email protected]. Include the frame rate, DF/NDF choice, input and expected output. Do not send confidential footage or private project material.