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Video Timecode Calculator

Video & AudioMedia Utilities

Hours, minutes, seconds and frames separated by colons.

Operation
Result timecode —
Result in frames
—
Result in seconds
—
Timecode A in frames
—
Timecode B in frames
—

To add or subtract timecodes, convert each to frames, do the arithmetic, then convert back. At 30 fps, 00:10:00:00 is 18,000 frames and 00:01:30:15 is 2,715 frames; the difference, 15,285 frames, is 00:08:29:15. The frame field always carries into seconds at the frame rate, not at 100.

About this tool

Editors, assistant editors and subtitlers spend a lot of time working out clip durations from in and out points, or offsetting a cue by a fixed amount. Doing it by hand is error-prone because the last field counts frames, which carry into seconds at 24, 25 or 30 rather than at 60 or 100. This calculator takes two timecodes in HH:MM:SS:FF form, adds or subtracts them at the frame rate you pick, and shows the result as timecode, as a frame count and as a seconds value, with each step of the conversion written out. It uses non-drop-frame counting only: for 29.97 fps drop-frame timecode, which skips frame numbers 00 and 01 at most minute boundaries, the result here can be off by up to two frames per minute.

How to use it

  1. Enter timecode A

    Type the first timecode as HH:MM:SS:FF, for example an out point of 00:10:00:00.

  2. Choose add or subtract

    Pick A + B to offset a timecode, or A − B to get the duration between two points.

  3. Enter timecode B and the frame rate

    Type the second timecode and select the project frame rate; 23.976 material counts as 24.

  4. Read the result

    The result shows as timecode, total frames and seconds, with the conversion steps below.

Examples

Last frame of the hour plus one

Timecode A
00:59:59:24
Operation
A + B
Timecode B
00:00:00:01
Frame rate
25 fps (PAL)

Result Result timecode: 01:00:00:00
Result in frames: 90,000
Result in seconds: 3,600
Timecode A in frames: 89,999
Timecode B in frames: 1

  1. Timecode A = 00:59:59:24 = 89999 frames at 25 fps
  2. Timecode B = 00:00:00:01 = 1 frames
  3. 89999 + 1 = 90000 frames
  4. 90000 frames ÷ 25 = 01:00:00:00

At 25 fps frames count 00 to 24, so adding a single frame to 00:59:59:24 carries into the hour: 01:00:00:00.

Clip length from in and out points at 30 fps

Timecode A
00:10:00:00
Operation
A − B
Timecode B
00:01:30:15
Frame rate
30 fps non-drop

Result Result timecode: 00:08:29:15
Result in frames: 15,285
Result in seconds: 509.5
Timecode A in frames: 18,000
Timecode B in frames: 2,715

  1. Timecode A = 00:10:00:00 = 18000 frames at 30 fps
  2. Timecode B = 00:01:30:15 = 2715 frames
  3. 18000 − 2715 = 15285 frames
  4. 15285 frames ÷ 30 = 00:08:29:15

18,000 frames minus 2,715 frames leaves 15,285 frames, which is 8 minutes 29 seconds and 15 frames.

Adding 20 frames at 24 fps

Timecode A
01:00:00:12
Operation
A + B
Timecode B
00:00:00:20
Frame rate
24 fps (also 23.976)

Result Result timecode: 01:00:01:08
Result in frames: 86,432
Result in seconds: 3,601.333
Timecode A in frames: 86,412
Timecode B in frames: 20

  1. Timecode A = 01:00:00:12 = 86412 frames at 24 fps
  2. Timecode B = 00:00:00:20 = 20 frames
  3. 86412 + 20 = 86432 frames
  4. 86432 frames ÷ 24 = 01:00:01:08

12 + 20 = 32 frames, which is one second (24 frames) and 8 frames, giving 01:00:01:08.

How it is calculated

frames = ((H × 60 + M) × 60 + S) × fps + F; result = A ± B; then H, M, S, F are recovered by dividing by fps, 60 and 60.

H, M, S, F
hours, minutes, seconds and frames of a timecode
fps
the nominal frame rate (frames per second)
A, B
the two timecodes expressed as frame counts

Each timecode is turned into a single frame count, so carries between fields happen automatically. After adding or subtracting, the frame count is split back: the remainder after dividing by fps is the frame field, and the whole seconds are split into hours, minutes and seconds. Non-drop-frame counting is used, as defined for integer rates in SMPTE ST 12-1.

When not to use it

  • Drop-frame 29.97 or 59.94 timecode needs drop-frame arithmetic, which this tool does not do.
  • Audio sample-accurate edits need sample counts, not frame counts.
  • Feet-and-frames film counts use a different notation.

Common mistakes

  • Treating the frame field as hundredths of a second, so 00:00:01:15 at 25 fps becomes 1.15 s instead of 1.6 s.
  • Mixing timecodes from projects with different frame rates.
  • Forgetting that an out point is often exclusive, so the duration is out minus in without adding a frame.
  • Entering a frame number equal to the frame rate, such as :25 at 25 fps, which does not exist.

Frequently asked questions

Why does 23.976 fps use the 24 fps setting?

23.976 material is labelled with 24-frame timecode: the frame field counts 00 to 23 and the numbers are identical. Only the real-time duration differs, running about 0.1 % longer than the timecode says, so the seconds figure here is nominal.

What is drop-frame timecode?

At 29.97 fps, counting 30 frames per second drifts about 3.6 seconds per hour behind the clock. Drop-frame timecode skips frame numbers 00 and 01 at the start of every minute except each tenth minute so the label stays close to real time. No frames are discarded, only numbers.

How do I get a clip duration from in and out points?

Put the out point in timecode A, the in point in timecode B and choose A − B. If your editor treats the out point as inclusive, add one frame to the result.

Can the result go past 24 hours?

Yes. The calculator keeps counting hours above 23 and shows a note, since most decks and editing systems wrap timecode at 24 hours back to 00:00:00:00.

Why is the result negative?

When subtracting, a timecode B later than A gives a negative frame count. The result is shown with a minus sign so you can see by how much B overshoots A.

Which separators can I type?

Colons are standard, but semicolons and full stops between fields are also accepted, so 01;00;00;00 copied from a drop-frame display still parses as non-drop arithmetic.

Cite this tool

Using this tool in an assignment, article or report? Copy a citation, or a link for your website.

APA

Tools Directory Editorial Team. (2026, October 24). Video Timecode Calculator. Tools Directory. Retrieved October 27, 2026, from https://tools.milunir.com/video-audio/media-utilities/video-timecode-calculator/

MLA

Tools Directory Editorial Team. “Video Timecode Calculator.” Tools Directory, 24 Oct. 2026, https://tools.milunir.com/video-audio/media-utilities/video-timecode-calculator/. Accessed 27 Oct. 2026.

Chicago

Tools Directory Editorial Team. “Video Timecode Calculator.” Tools Directory. Last modified October 24, 2026. Accessed October 27, 2026. https://tools.milunir.com/video-audio/media-utilities/video-timecode-calculator/.

Link<a href="https://tools.milunir.com/video-audio/media-utilities/video-timecode-calculator/">Video Timecode Calculator – Tools Directory</a>