SMPTE Drop-Frame Timecode Calculator

Convert between video timecode and total frames, calculate wall-clock drift, and accurately manage SMPTE 12M drop-frame arithmetic.

Calculator

Timecode
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Total Frames
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Real Time (Wall Clock)
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Drift (vs Timecode)
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Batch Converter & Export

Paste multiple timecodes or frame counts (one per line). Auto-detects input format.

System Diagnostics

Run built-in golden tests for Drop-Frame arithmetic correctness.

About the SMPTE Drop-Frame Timecode Calculator

Editors, broadcast engineers, and post-production teams use a SMPTE drop-frame timecode calculator to convert between timecode, frame counts, and real running time at 29.97 fps. It clarifies the difference between drop-frame counting and non-drop-frame counting, reducing timing errors in program masters, captions, deliverables, and edit decision lists.

How it works

  1. Choose the frame rate and select drop-frame or non-drop-frame counting.
  2. Enter a timecode, frame count, or real-time duration.
  3. Convert the value into the other timing formats.
  4. Check boundary cases such as hour marks, minute marks, and deliverable durations.
  5. Use the result in edit notes, caption timing, or broadcast paperwork.

Frequently asked questions

Does drop-frame timecode remove video frames?

No. Drop-frame timecode skips certain frame numbers so the counter stays aligned with real time at 29.97 fps. The video frames themselves are not removed.

Why is 29.97 timecode different from 30 fps timecode?

NTSC-derived video runs at approximately 30000 over 1001 frames per second. Non-drop-frame counting drifts against clock time, while drop-frame numbering compensates for that drift.

When should I use non-drop-frame timecode?

Use non-drop-frame when the delivery specification, camera workflow, or post facility requires continuous frame numbering. It is common in some production and editorial contexts but does not match clock time over long durations at 29.97 fps.

Why are frames dropped at most minutes but not every tenth minute?

That numbering pattern keeps 29.97 fps timecode closely aligned with real elapsed time. Every tenth minute is left unskipped so the count remains correct across each ten-minute block.

References