Timecode Calculator

Knowledge Base

Why Timecode Math Isn't Just Clock Math

Timecode looks like a clock (HH:MM:SS:FF) but doesn't behave like one. The frame count per second depends on your frame rate, and 29.97/30 fps drop-frame timecode deliberately skips frame numbers to keep long-form timecode in sync with real wall-clock time, so naive HH:MM:SS:FF addition gives the wrong answer unless you convert through total frame counts first, which is what this tool does.

Drop-Frame vs Non-Drop-Frame

Drop-frame (DF) timecode skips frame numbers 00 and 01 at the start of every minute except every 10th minute, which keeps 29.97 fps timecode matching real-world clock time over long recordings. Non-drop-frame (NDF) counts every frame and drifts about 3.6 seconds per hour against wall-clock time. Broadcast delivery almost always specifies which one to use, mixing them on the same project causes sync errors.

When You'd Use This

• Working out the timecode of a cut point a known duration into a clip.
• Confirming a program's total runtime by adding segment timecodes together.
• Checking how far apart two logged shot timecodes are.

FAQ

Q: Why does subtracting give a huge timecode instead of going negative?
A: Timecode wraps at 24 hours. If B is larger than A, the result wraps around from 23:59:59:xx rather than showing a negative value. Treat a result close to 24:00:00:00 as effectively negative.

Q: Does the frame rate of A and B have to match?
A: Yes. This tool assumes both timecodes are at the frame rate you select above. Convert one first with the Frame Rate Converter if your sources differ.