# Timecode Calculator

> Add and subtract video timecodes (HH:MM:SS:FF) for calculating show runtimes

**Category:** Media
**Keywords:** timecode, SMPTE timecode, video editing, show runtime, timecode math, frame counter, edit duration
**URL:** https://complete.tools/timecode-calculator

## How timecode math works

Timecode arithmetic converts each timecode into a total frame count, performs the addition or subtraction, and converts the result back to HH:MM:SS:FF format.

**Formula:**
```
Total Frames = (Hours x FPS x 3600) + (Minutes x FPS x 60) + (Seconds x FPS) + Frames
```

**Where:**
- **FPS** = the nominal frame rate (24, 25, 30, etc.)
- **Frames** = the frame number within the current second (starting from 0)

For drop-frame timecode at 29.97 fps, the conversion uses the SMPTE 12M formula that accounts for skipped frame numbers. Two frame numbers (00 and 01) are skipped at the start of each minute, except every 10th minute, to keep the timecode synchronized with real-world clock time.

**Example:** Adding 01:00:00:00 + 00:30:00:00 at 24 fps
- Timecode A = 86,400 frames
- Timecode B = 43,200 frames
- Result = 129,600 frames = 01:30:00:00

## Frame rates explained

Different frame rates are used depending on the delivery format and region:

- **23.976 fps** — Digital cinema and most streaming content. Technically 24000/1001 fps, used for material that originated on film and is delivered digitally.
- **24 fps** — True film frame rate used in theatrical projection and some digital cinema workflows.
- **25 fps (PAL)** — Standard for broadcast television in Europe, Australia, and most of Asia and Africa. Matches the 50 Hz power grid frequency.
- **29.97 fps Drop-Frame** — North American broadcast standard. Uses semicolons (;) before the frame number and skips certain frame counts to keep timecode aligned with wall-clock time over long durations.
- **29.97 fps Non-Drop** — Same frame rate as drop-frame but without the frame-skipping compensation. Timecode gradually drifts from real time (about 3.6 seconds per hour). Used when frame-accurate counting matters more than clock accuracy.
- **30 fps** — Used in some digital production workflows and web video.
- **50 fps** — High frame rate PAL, used for slow-motion or high-quality broadcast.
- **59.94 fps** — High frame rate NTSC, common for sports broadcasts and slow-motion in North America.
- **60 fps** — High frame rate digital, used in gaming capture and some web video.

## How to use

1. Select your project's frame rate from the dropdown menu
2. Enter Timecode A using the hours, minutes, seconds, and frames fields
3. Choose whether to add or subtract
4. Enter Timecode B in the same format
5. View the result timecode, total frame count, and duration in seconds instantly

The calculator validates your input in real time. If you enter a frame number that exceeds the maximum for your selected frame rate, you will see a warning and the value will be clamped to the valid range.

## FAQs

**
**Q:** What is the difference between drop-frame and non-drop-frame timecode?**


**A:** Drop-frame timecode skips frame numbers 00 and 01 at the start of each minute (except every 10th minute) to compensate for the fact that 29.97 fps is not exactly 30 fps. This keeps the timecode synchronized with real-world clock time. Non-drop-frame timecode counts every frame sequentially but gradually drifts from wall-clock time by about 3.6 seconds per hour. Drop-frame uses semicolons (;) before the frame number, while non-drop uses colons (:).

**
**Q:** Why does my timecode show semicolons instead of colons?**


**A:** Semicolons before the frame number indicate drop-frame timecode. This is the standard notation defined by SMPTE to visually distinguish drop-frame from non-drop-frame timecodes. If you see 01:00:00;00, you are working in drop-frame mode.

**
**Q:** Can I get a negative result?**


**A:** Yes. If you subtract a longer timecode (B) from a shorter one (A), the result will be negative. The calculator displays a minus sign before the timecode and shows a warning. This can be useful for determining how much time remains or how far apart two timecodes are.

**
**Q:** What frame rate should I use for my project?**


**A:** Use the frame rate that matches your project settings. For North American broadcast, use 29.97 drop-frame. For European broadcast, use 25 fps. For film and most streaming content, use 23.976 or 24 fps. Check your editing software's project settings if you are unsure.

**
**Q:** How accurate is the drop-frame calculation?**


**A:** The calculator uses the standard SMPTE 12M drop-frame formula, which is the same algorithm used in professional editing systems like Avid Media Composer, Adobe Premiere Pro, and DaVinci Resolve. The results are frame-accurate.

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*Generated from [complete.tools/timecode-calculator](https://complete.tools/timecode-calculator)*