Free Tool for Video Editors

TC-100 Timecode Calculator

A calculator built specifically for editors who work in drop-frame and non-drop-frame timecode — add, subtract, multiply, and divide timecodes without doing the SMPTE math in your head.

Try it right now — no download needed

Want to test it before installing anything? The full calculator runs right in your browser, in its own window.

Why this exists

Drop-frame timecode is deceptively easy to get wrong. Certain frame numbers — :00 and :01 at the start of most minutes — simply don’t exist, skipped on purpose so the timecode stays roughly in sync with real clock time. Add two timecodes together by hand, or in a calculator that doesn’t understand the rule, and you can end up a few frames off without realizing it. TC-100 handles that correction automatically, every time.

What it does

• Full drop-frame and non-drop-frame support at 60, 59.94, 30, 29.97, 24, and 23.976 fps, plus any custom frame rate you need.
• Add, subtract, multiply, and divide timecodes the way you’d expect from a real calculator — type digits, press an operator, keep going.
• Chain calculations like an adding-machine tape: keep adding clip durations one after another, or hit = again to repeat the last operation.
• A built-in history log so you can review your work or jump back to an earlier result with one click.
• Memory keys (M+, M−, MR, MC) for holding a running total while you work through other numbers.
• Runs standalone on Mac — no install of any other software required — or right in your browser with no install at all.

Download

TC-100 is free.

First launch note (Windows): since this is independently distributed software, Windows will show a “Windows protected your PC” warning the first time you open it. Click More info, then Run anyway. This only happens once.

First launch note (Mac): since this is independently distributed software, your Mac may show a one-time verification step the first time you open it, depending on how it was downloaded. This is normal and only happens once.

How it works

Timecode entry works like setting a clock — type digits and they shift in from the right as HH:MM:SS:FF. Choose a frame rate at the top; drop-frame mode (shown with a semicolon before the frames, like ;02, instead of a colon) switches on automatically for 29.97 and 59.94, and can be toggled for custom rates too.

Add 1:00;00 to 1:00;02 and TC-100 correctly returns 2:00;02 — accounting for the drop-frame rule automatically, the same way a real broadcast deck would.

TC-100 is part of the RampantOctopus Softworks suite of free and paid tools for Video Editors and Producers — including XML2Excel, which turns your finished sequence into a delivery-ready Excel workbook.