Slow Motion Calculator – Slowdown Factor & Output Duration Calculator
Calculate slow motion playback duration and slowdown factor from recording and playback frame rates with our free slow motion calculator. Whether you record at 120fps, 240fps, or 960fps on your smartphone, instantly find out how long your clip will appear in slow-motion playback. This slow-mo FPS calculator helps videographers plan shots and understand the relationship between capture rate and final slow-motion duration.
Slow Motion Calculator
Calculate slow-mo factor and output duration
Slow Motion Calculator Features
- Calculates the slowdown factor from recording FPS versus playback FPS
- Determines the final output video duration after slow-motion processing
- Accepts recording FPS (e.g., 960), playback FPS (e.g., 30), and recorded duration
- Useful for planning slow-motion shots before recording on smartphones
- Supports all common slow-motion modes: 120fps, 240fps, 480fps, 960fps
- Displays slowdown multiplier clearly alongside the stretched output duration
How to Use Slow Motion Calculator
- Enter the recording frame rate in fps (e.g., 960) in the “Recording FPS” field
- Enter the playback frame rate in fps (e.g., 30) in the “Playback FPS” field
- Enter the duration of the recorded clip in seconds (e.g., 5) in the “Recorded Duration” field
- Click the Calculate button
- View the slowdown factor (e.g., 32x) and the output video duration in seconds in the results
- Click Reset to calculate for a different slow-motion configuration
Frequently Asked Questions
Slow Motion Duration = Real Duration × (Recording FPS ÷ Playback FPS). A 1-second clip at 240fps played at 30fps = 8 seconds of slow motion (8× slowdown factor).
Standard slow-mo = 120fps (4× at 30fps playback). Smooth slow-mo = 240fps (8×). Extreme slow-mo = 960fps (32×). Higher frame rates create more dramatic slow motion effects but reduce video quality and resolution.
Samsung Galaxy S series (from S9+), Sony Xperia 1 series, and some Xiaomi flagships support 960fps “super slow motion.” Note that most only record at lower resolution (720p or 1080p) at 960fps.
High-frame-rate recording captures more frames per second, generating more data and thus larger raw files. However, the playback duration is extended, so final exported slow-motion videos may have similar bitrates to normal video.
You can apply slow motion in editing, but unless the original was recorded at high frame rates, artificial slow-down creates stuttery, low-quality results (frame blending or frame interpolation). For smooth slow motion, record at high FPS.
120fps = 4× slowdown at 30fps playback (moderate slow-mo). 240fps = 8× slowdown (very smooth slow-mo). 240fps files are approximately twice as large as 120fps files for the same duration of real-time action.
Most smartphones support 240fps at 1080p (Full HD). Some flagship models support 240fps at 4K. 960fps is typically limited to 720p on even flagship devices due to sensor data read-out speed limitations.
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