What fps is my video?
Open it here and read the frame rate in Video. You get the minimum, average and maximum measured from the real frame timing, so you also see whether the rate holds steady.
Free · runs in your browser
Check a video’s frame rate (fps) and spot variable frame rate
See the real frame timing of any video, not only the number in its header, and find out whether a phone clip will behave in an editor.
To check the fps of a video, open it here and read the frame rate in the Video section. Rather than trusting only the rate written in the file’s header, the checker measures the real time between frames and reports the minimum, average and maximum, so you can tell an exact 30 fps from 29.97 and spot variable frame rate footage that only claims to be 30.
That matters because phones rarely record a perfectly even frame rate. They stretch the gap between frames in dim light, which is invisible when you watch the clip but can make sound drift out of sync in some video editors. The Device section adds the capture frame rate where the camera stores one, which explains slow-motion files that play at a different speed from how they were filmed.
Everything is read in your browser; the video is not uploaded. Frame rate sits next to resolution and bitrate in the same section, so the resolution checker and bitrate checker open on the same view.
How to check the frame rate of a video
Open the file
Press Open a file (Ctrl/Cmd+O) or drop the video on Drop a video or photo here. MP4, MOV, MKV, WebM, AVI and camcorder files all work.
Read the frame rate in Video
The Video section shows the frame rate, so you can see at a glance whether the clip is 24, 25, 29.97, 30, 60 or something else. The ⓘ explains what the value means.
Check for variable frame rate
Look at the minimum, average and maximum measured from the frame timing. If they differ, the file is marked as variable frame rate.
Check the capture rate for slow motion
Press
JorKto move to Device. Where the camera records it, the capture frame rate shows how fast the clip was filmed, which can differ from the playback rate.
Common frame rates and where they come from
| Frame rate | Exact value | Where it is used |
|---|---|---|
| 23.976 fps | 24000/1001 | Film-style video in former NTSC regions (North America, Japan) |
| 24 fps | 24/1 | Cinema; the “film look” setting on cameras and phones |
| 25 fps | 25/1 | TV and video in former PAL regions (UK, Europe, Australia, much of Asia and Africa) |
| 29.97 fps | 30000/1001 | TV and most phone and camera video in former NTSC regions |
| 30 fps | 30/1 | Screen recordings, webcams, some phones and games |
| 50 fps | 50/1 | Smooth motion and sport in PAL regions |
| 59.94 fps | 60000/1001 | Smooth motion and sport in NTSC regions |
| 60 fps | 60/1 | Games, screen recordings, some phones |
| 120 / 240 fps | 120/1, 240/1 | Slow-motion capture |
Why 29.97 instead of 30
When colour was added to American television in the 1950s, the frame rate was lowered by 0.1 per cent so the new colour signal would not interfere with the sound carrier. The fractional rates stuck, and cameras and phones sold in those regions still record 29.97 and 59.94 by default.
Mixing the two families in one edit causes small judders or dropped frames, so it is worth checking clips from different cameras before you start. iPhones offer PAL formats (HD (PAL) and 4K (PAL) at 25 fps) under Settings > Camera > Record Video for people working to 25 fps.
Constant and variable frame rate
In a constant frame rate (CFR) file, every frame lasts exactly the same time: 1/25 of a second at 25 fps. In a variable frame rate (VFR) file, each frame carries its own timestamp and the gaps can change from moment to moment. Players handle both without complaint. The difference shows up when you edit.
Why phone video is often variable
- Low light. A longer exposure per frame means fewer frames per second. Apple’s Auto FPS setting, for example, drops the frame rate to 24 fps in low light; it is under Settings > Camera > Record Video.
- Processing load. If the phone gets hot or busy, it may skip or delay frames rather than stop recording.
- Screen recorders and video calls often record a new frame only when the screen changes, producing very uneven timing.
Why editors care
Many editing programs are built around a constant frame rate and assume every frame lasts the same time. With VFR footage, some of them place frames at slightly wrong times, and over a long clip the picture slowly drifts away from the sound. Short clips rarely show it; a 20-minute talk recorded on a phone can end up visibly out of sync.
How to fix variable frame rate
The only real fix is to re-encode the clip to a constant frame rate before editing. Some editors offer to do this on import; HandBrake has a constant frame rate option; ffmpeg can do it in one command. Pick the rate the clip mostly ran at, usually the average the checker reports.
ffmpeg -i input.mov -fps_mode cfr -r 30 -c:v libx264 -crf 18 -c:a copy output.mp4
Re-encoding always costs a little quality. A low crf value such as 18 keeps the loss small at the cost of a bigger file. metadata.video measures VFR but does not convert it.
Slow motion: filmed fast, played slow
Slow motion works by capturing many frames per second and playing them back at a normal rate. An iPhone’s Slo-mo mode, for instance, records 1080 HD at 240 fps on the back camera by default (120 fps on the front). Depending on the phone and the app that saved it, the file you end up with may:
- hold every captured frame at the high rate, with the slow part decided by the phone’s gallery app when it plays (which is why the clip can run at normal speed on a computer), or
- already be stretched out, with a normal playback rate such as 30 fps and the high rate kept only as a capture value.
Comparing the frame rate in Video with the capture frame rate in Device tells you which kind you have. A playback rate of 30 with a capture rate of 240 means the clip has been slowed down eight times.
Which frame rate should you use?
| Goal | Usual choice |
|---|---|
| A cinematic look | 24 fps (23.976 in NTSC regions) |
| General video in the UK and Europe | 25 fps, or 50 for smoother movement |
| General video in North America | 30 fps (29.97), or 60 (59.94) |
| Sport, fast action, gameplay | 50 or 60 fps |
| Slow motion in the edit | 120 or 240 fps, played back at 24–30 |
| Smallest files | The lowest rate that suits the subject; 60 fps needs noticeably more bitrate than 30 |
The best frame rate for 4K video is the same as for any other resolution: it depends on the subject and where the video will be shown. Doubling the frame rate roughly doubles the work for the encoder and raises the bitrate needed for the same quality; YouTube’s recommended upload bitrates for 48–60 fps are about 1.5 times those for 24–30 fps. YouTube also asks you to upload at the frame rate you recorded rather than converting, which is good advice for any platform.
Other ways to check frame rate
- Windows: File Explorer > right-click the file > Properties > Details tab > Frame rate. It shows the header value only, so it can’t reveal VFR.
- Mac: QuickTime Player > Window > Show Movie Inspector (Command-I) lists the frame rate.
- VLC: Tools > Codec Information (Ctrl+J) shows the frame rate of the video stream.
- ffprobe: compares the nominal rate with the average and can count every frame. The ffprobe guide explains more fields.
ffprobe -v error -select_streams v:0 -count_frames -show_entries stream=r_frame_rate,avg_frame_rate,nb_read_frames,time_base -of default=nw=1 file.mp4
If r_frame_rate and avg_frame_rate differ noticeably, the file is probably VFR. time_base is the unit the timestamps are counted in, such as 1/600 in many iPhone files.
Frame rate: common questions
Is 60 fps better than 30 fps?
60 fps makes movement smoother, which suits sport and games, and allows smooth half-speed slow motion. It also needs more bitrate and storage, and some people find it looks less cinematic than 24 or 30.
Why does my video say 29.97 fps instead of 30?
29.97 (exactly 30000/1001) is the standard rate in former NTSC regions, kept from the change to colour television. Phones and cameras sold there use it by default. It plays the same as 30 for viewing purposes.
How do I fix variable frame rate?
Re-encode the clip to a constant frame rate in your editor, HandBrake or ffmpeg before editing. Choose the rate the clip mostly used, such as 30 or 25.
Why does audio drift out of sync when I edit phone footage?
Phone clips are often variable frame rate, and some editors assume every frame has the same length. Over a long clip the small timing errors add up. Converting to a constant frame rate first prevents it.
Why does my slow-motion video play at normal speed on a computer?
Some phones save every captured frame at the high rate and let their own gallery app decide which part plays slowly. Other players show it at normal speed. Exporting or sharing the clip from the phone usually produces a version with the slow motion built in.
Is my video uploaded to check the frame rate?
No. Frame timing is read from the file on your device; nothing is sent to a server.