Batch Timecode Calculator

Knowledge Base

What It Actually Computes

Give it a start timecode, a frame rate, and a list of clip names with durations in seconds. It walks through the list in order, computing each clip's in-point (immediately after the previous clip's out-point) and out-point (in-point plus the clip's duration, converted to frames at your chosen rate): the same arithmetic you'd do by hand for a shot log or EDL, just instant and error-free across dozens of clips.

Frame Rates Supported

23.976, 24, 25, 29.97 (drop-frame and non-drop), 30 (drop-frame and non-drop), 50, 59.94, and 60 fps. Drop-frame timecode is calculated using the standard SMPTE drop-frame algorithm, the same one used by the site's browser-based Timecode Calculator, so results match whichever tool you use.

Why This One Isn't a Browser App

Every other tool on this site runs entirely in your browser by design, no upload, no install. This one is different on purpose: it's a genuinely native app so it can offer real file export (a CSV you can hand off to an editor or import into a spreadsheet) without any of the file-permission friction a browser sandbox would add for that kind of workflow.

FAQ

Q: Is this actually free?
A: Yes, free and open-source under the MIT license. No account, no trial, no watermark.

Q: Will I get a security warning when I open it?
A: Possibly, until code-signing is set up for this project, unsigned apps trigger a standard OS warning on first launch (Gatekeeper on macOS, SmartScreen on Windows). The app itself is unaffected. You can review the source on GitHub before running it if you'd like to verify that yourself.

Q: Can I use it without an internet connection?
A: Yes, once installed it runs entirely offline, nothing about your clip list or timecodes is ever sent anywhere.

Working with lists of durations

Timecode arithmetic is base sixty for two of its fields and base frame rate for the third, so ordinary calculators get it wrong. Adding 00:00:45:20 to 00:01:30:15 needs the frames field to roll over at whatever the frame rate is rather than at 100, and doing a page of these by hand is where errors enter a delivery.

Running totals are the common need. Adding up segment durations to check a programme hits its slot, working out where an item lands after three others, and confirming a cut list sums to the stated length are all the same operation repeated, which is exactly what a batch tool is for.

Mixing frame rates in one calculation is the mistake to watch for. A list of durations at 25 frames per second and another at 23.976 cannot be added meaningfully without conversion, and the result looks plausible while being wrong. Confirm every duration in a batch shares one rate before summing.

Drop-frame changes what the numbers mean. At 29.97 drop-frame the counting skips values, so a straightforward subtraction between two timecodes does not give elapsed frames unless the calculation accounts for the skipped numbers. Getting this wrong produces small errors that grow across a long programme.

A desktop application handles this better than a browser for one practical reason. The work usually involves a list pasted from a spreadsheet or exported from an edit, and a native application handles clipboard content, large lists and file input without the constraints a browser page works under.

Vocabulary

Timecode arithmetic. Adding or subtracting timecode values, where seconds and minutes roll over at sixty and frames roll over at the frame rate. Ordinary decimal calculation gives wrong answers.

Running total. A cumulative sum across a list of durations, used to check a programme fits its slot or to find where an item begins. The most common reason to calculate timecode in bulk.

Drop-frame. A counting scheme skipping certain frame numbers so timecode stays aligned with clock time at 29.97 frames per second. Means arithmetic must account for the skipped values rather than counting straight through.

Conform. Bringing material to a common frame rate so it can be edited or calculated together. Necessary before summing durations from sources recorded at different rates.