What is drop-frame timecode?

Drop-frame (DF) timecode skips frame numbers 00 and 01 at the start of each minute, except every 10th minute. This keeps wall-clock time and timecode aligned for 29.97 fps video. The separator is a semicolon (;) instead of a colon (:).

When should I use drop-frame vs non-drop-frame?

Use drop-frame (29.97 DF or 59.94 DF) for broadcast TV where timecode must match wall-clock time. Use non-drop-frame for film, music videos, or when exact frame counts matter more than clock alignment.

What does the FF field mean in HH:MM:SS:FF?

FF is the frame count within the current second, starting at 00. At 25 fps it runs 00–24; at 29.97 NDF it runs 00–29. The valid range changes with the selected frame rate.

What is 23.976 fps used for?

23.976 fps (24000/1001) is the standard for cinema content delivered to NTSC markets. It is non-drop-frame only.

How are drop-frame frame numbers calculated?

The SMPTE 12M formula is: frames = base * 3600 * h + (base * 60 - D) * m + D * floor(m / 10) + base * s + f, where D = 2 for 29.97 and D = 4 for 59.94.

Frame-Accurate Timecode Calculator

Name: Frame-Accurate Timecode Calculator
Availability: InStock
Author: Nham Vu

Convert between SMPTE timecode (HH:MM:SS:FF) and frame numbers for 23.976, 24, 25, 29.97 DF/NDF, 30, 50, 59.94 DF/NDF, and 60 fps.

Frame Rate

Conversion Direction

Input

SMPTE Timecode

: : :

HH:MM:SS:FF — frame field 00–29

Result

Enter a value above and click Convert

Copied!

Summary

Convert between SMPTE timecode (HH:MM:SS:FF) and frame numbers for 23.976, 24, 25, 29.97 DF/NDF, 30, 50, 59.94 DF/NDF, and 60 fps.

How it works

Select a frame rate — drop-frame options (DF) are available for 29.97 and 59.94 fps.
Enter a SMPTE timecode (HH:MM:SS:FF, or HH:MM:SS;FF for drop-frame) or a frame number.
Click Convert to see both the timecode and the frame number simultaneously.
Use the copy buttons to grab either value for your NLE, script, or EDL.
Switch direction with the TC → Frame / Frame → TC toggle at any time.

Use cases

Find the frame number that corresponds to a SMPTE timecode in an NLE timeline.
Convert a raw frame number to timecode for logging or EDL creation.
Verify drop-frame timecode calculations when editing NTSC broadcast video.
Calculate the correct timecode offset when syncing audio to picture.
Check timecode math when splitting or joining clips in post-production.
Validate timecode accuracy in automation scripts that process video files.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu